Increased competition during the early 1900s from the new International Harvester Company led the company to expand its offerings in the implement business, but the production of gasoline tractors came to define Deere & Company's operations during the 20th century.

 
In 1912, Deere & Company president William Butterworth (Charles' son-in-law), who had replaced Charles Deere after his death in 1907, began the company's expansion into the tractor business.
Deere & Company briefly experimented with its own tractor models, the most successful of which was the Dain All-Wheel-Drive, but in the end decided to continue its foray into the tractor business by purchasing the Waterloo Gasoline Engine Company in 1918, which manufactured the popular Waterloo Boy tractor at its facilities in Waterloo, Iowa.
Deere & Company continued to sell tractors under the Waterloo Boy name until 1923 when the John Deere Model D was introduced.
The company continues to manufacture a large percentage of its tractors in Waterloo, Iowa, namely the 7R, 8R, and 9R series.

The company produced its first combine harvester, the John Deere No.
2, in 1927.
A year later, this innovation was followed up by the introduction of John Deere No.
1, a smaller machine that was more popular with customers.
By 1929, the No.
1 and No.
2 were replaced by newer, lighter-weight harvesters.
In the 1930s, John Deere and other farm equipment manufacturers began developing hillside harvesting technology.
Harvesters now had the ability to effectively use their combines to harvest grain on hillsides with up to a 50% slope gradient.

On an episode of the Travel Channel series Made in America that profiled Deere & Company, host John Ratzenberger stated that the company never repossessed any equipment from American farmers during the Great Depression.

During World War II, the great-grandson of John Deere, Charles Deere Wiman, was president of the company, but he accepted a commission as a colonel in the U.S. Army.
A replacement was hired and before returning to work at the company in late 1944, Wiman directed the farm machinery and equipment division of the War Production Board.
In addition to farm machinery, John Deere manufactured military tractors, and transmissions for the M3 tank.
They also made aircraft parts, ammunition, and mobile laundry units to support the war effort.

In 1947, John Deere introduced its first self-propelled combine, model 55.
It was soon followed by the smaller models 40 and 45, the larger model 95, and an even larger model 105 was introduced in the 1960s.
In the mid-1950s, Deere introduced attachable corn heads, allowing crop producers to cut, shell, and clean corn in one smooth operation.

In 1956, Deere & Company bought-out the German tractor manufacturer, Heinrich Lanz AG (see Lanz Bulldog).

In the last months of 1958, John Deere constructed a factory in northern Rosario, Argentina.
In Argentina, the make was managed by Agar Cross & Co.
John Deere made in Argentina the following models of tractors: 445, 730; the models of the serie 20 like 1420, 2420, 3420, 4420; the models of the serie 30 like 2330, 2530, 2730, 3330, 3530, 4530; the models of the serie 40 like 2140, 3140 / 3140 DT, 3440, 3540 and the last made in Baigorria of the serie 50 like 2850, 3350, 3550 until 1994.

Seventeen years later, (in 2011) the Argentinian plant returns the assembly of tractors with the following models: 5036C, 5045D (45 HP) Serie 5D, 5045E (45 HP) Serie 5E, 5065E (65 HP) Serie 5E, 5075E (75 HP) Serie 5E, 5425N (77 HP) Serie 5000, 5725 (92 HP) Serie 5025, 5725HC (92 HP) Serie 5025, 5090E, 5090EH, 5076EF, 6110J, 6130J, 6145J and 6165J.
Plus, in 2012, added in SKD/CKD format, the assembly of combine harvesters 9570 STS Serie 70, 9470 STS, 9670 STS and 9770 STS.

Also with the green line, the Argentinian facility made some backhoe loaders and motor graders like 570 A/B, 544 A/B, 507, 308, 200 and the 627, 727 model tractors.

On August 30, 1960, John Deere dealers from around the world converged on Dallas, Texas, for an unprecedented product showcase.
Deere Day in Dallas, as th
Increased competition during the early 1900s from the new International Harvester Company led the company to expand its offerings in the implement business, but the production of gasoline tractors came to define Deere & Company's operations during the 20th century.
 
In 1912, Deere & Company president William Butterworth (Charles' son-in-law), who had replaced Charles Deere after his death in 1907, began the company's expansion into the tractor business. Deere & Company briefly experimented with its own tractor models, the most successful of which was the Dain All-Wheel-Drive, but in the end decided to continue its foray into the tractor business by purchasing the Waterloo Gasoline Engine Company in 1918, which manufactured the popular Waterloo Boy tractor at its facilities in Waterloo, Iowa. Deere & Company continued to sell tractors under the Waterloo Boy name until 1923 when the John Deere Model D was introduced. The company continues to manufacture a large percentage of its tractors in Waterloo, Iowa, namely the 7R, 8R, and 9R series.
The company produced its first combine harvester, the John Deere No. 2, in 1927. A year later, this innovation was followed up by the introduction of John Deere No. 1, a smaller machine that was more popular with customers. By 1929, the No. 1 and No. 2 were replaced by newer, lighter-weight harvesters. In the 1930s, John Deere and other farm equipment manufacturers began developing hillside harvesting technology. Harvesters now had the ability to effectively use their combines to harvest grain on hillsides with up to a 50% slope gradient.
On an episode of the Travel Channel series Made in America that profiled Deere & Company, host John Ratzenberger stated that the company never repossessed any equipment from American farmers during the Great Depression.
During World War II, the great-grandson of John Deere, Charles Deere Wiman, was president of the company, but he accepted a commission as a colonel in the U.S. Army. A replacement was hired and before returning to work at the company in late 1944, Wiman directed the farm machinery and equipment division of the War Production Board. In addition to farm machinery, John Deere manufactured military tractors, and transmissions for the M3 tank. They also made aircraft parts, ammunition, and mobile laundry units to support the war effort.
In 1947, John Deere introduced its first self-propelled combine, model 55. It was soon followed by the smaller models 40 and 45, the larger model 95, and an even larger model 105 was introduced in the 1960s. In the mid-1950s, Deere introduced attachable corn heads, allowing crop producers to cut, shell, and clean corn in one smooth operation.
In 1956, Deere & Company bought-out the German tractor manufacturer, Heinrich Lanz AG (see Lanz Bulldog).
In the last months of 1958, John Deere constructed a factory in northern Rosario, Argentina. In Argentina, the make was managed by Agar Cross & Co.
John Deere made in Argentina the following models of tractors: 445, 730; the models of the serie 20 like 1420, 2420, 3420, 4420; the models of the serie 30 like 2330, 2530, 2730, 3330, 3530, 4530; the models of the serie 40 like 2140, 3140 / 3140 DT, 3440, 3540 and the last made in Baigorria of the serie 50 like 2850, 3350, 3550 until 1994.
Seventeen years later, (in 2011) the Argentinian plant returns the assembly of tractors with the following models: 5036C, 5045D (45 HP) Serie 5D, 5045E (45 HP) Serie 5E, 5065E (65 HP) Serie 5E, 5075E (75 HP) Serie 5E, 5425N (77 HP) Serie 5000, 5725 (92 HP) Serie 5025, 5725HC (92 HP) Serie 5025, 5090E, 5090EH, 5076EF, 6110J, 6130J, 6145J and 6165J.
Plus, in 2012, added in SKD/CKD format, the assembly of combine harvesters 9570 STS Serie 70, 9470 STS, 9670 STS and 9770 STS.
Also with the green line, the Argentinian facility made some backhoe loaders and motor graders like 570 A/B, 544 A/B, 507, 308, 200 and the 627, 727 model tractors.
On August 30, 1960, John Deere dealers from around the world converged on Dallas, Texas, for an unprecedented product showcase. Deere Day in Dallas, as th
John Deere