On September 3, 1910, Robbins was married to Irene de Bruyn (1887–1960), a Belgian who was born and grew up in Buenos Aires, Argentina.
She was a daughter of Casimir de Bruyn, banker, railroad man, and capitalist who was then the head of the Banco Franco-Argentina.
Together, they were the parents of:
Warren Delano Robbins Jr. (1911–1979), who also went into the diplomatic service and served as attaché at the U.S. Embassy in Buenos Aires.

Edward Hutchinson Robbins (1912–1944), who married Louise Auchincloss (1914–1974), a daughter of Gordon Auchincloss (and niece of U.S. Representative James C. Auchincloss), in 1935.
After his death, she married developer Allston Boyer in 1947.

Irene Helen Robbins (b. 1914), who married Alexander Cochrane Forbes (1909–2005), a son of F. Murray Forbes (of Cabot, Cabot & Forbes) and first cousin of Alexander Cushing, in 1934.

He was a member of the Tuxedo Club, the Knickerbocker Club and the Brook Club in New York.
In Washington, he was a member of the Chevy Chase Club and Riding Club.

Robbins died of pneumonia at the Doctors Hospital in New York City on April 7, 1935, aged 49.
 After a service at the Church of the Incarnation, he was buried at Riverside Cemetery in Fairhaven, Massachusetts.
In 1936, Robbins' widow served as a special assistant at the All-American Conference for Maintenance of Peace in Buenos Aires.
 In 1937, Irene, an interior decorator, was appointed Assistant Chief of the State Department's Foreign Service Buildings Office, responsible for furnishing and decorating U.S. embassies, consulates and other facilities.
His widow died in Hyattsville, Maryland in 1960.
On September 3, 1910, Robbins was married to Irene de Bruyn (1887–1960), a Belgian who was born and grew up in Buenos Aires, Argentina. She was a daughter of Casimir de Bruyn, banker, railroad man, and capitalist who was then the head of the Banco Franco-Argentina. Together, they were the parents of:
Warren Delano Robbins Jr. (1911–1979), who also went into the diplomatic service and served as attaché at the U.S. Embassy in Buenos Aires.
Edward Hutchinson Robbins (1912–1944), who married Louise Auchincloss (1914–1974), a daughter of Gordon Auchincloss (and niece of U.S. Representative James C. Auchincloss), in 1935. After his death, she married developer Allston Boyer in 1947.
Irene Helen Robbins (b. 1914), who married Alexander Cochrane Forbes (1909–2005), a son of F. Murray Forbes (of Cabot, Cabot & Forbes) and first cousin of Alexander Cushing, in 1934.
He was a member of the Tuxedo Club, the Knickerbocker Club and the Brook Club in New York. In Washington, he was a member of the Chevy Chase Club and Riding Club.
Robbins died of pneumonia at the Doctors Hospital in New York City on April 7, 1935, aged 49.  After a service at the Church of the Incarnation, he was buried at Riverside Cemetery in Fairhaven, Massachusetts. In 1936, Robbins' widow served as a special assistant at the All-American Conference for Maintenance of Peace in Buenos Aires.  In 1937, Irene, an interior decorator, was appointed Assistant Chief of the State Department's Foreign Service Buildings Office, responsible for furnishing and decorating U.S. embassies, consulates and other facilities. His widow died in Hyattsville, Maryland in 1960.
Warren Delano Robbins