Đaja finished elementary and high school in Belgrade.
After graduating at First Belgrade Gymnasium in 1902, he moved back to France, spending one year as a student at the Lycée Pierre-Corneille at Rouen.
He studied philosophy under Émile Chartier.
In 1903 he enrolled at the Sorbonne, where one of his fellow students and best friends was Émile Herzog, later famous French author under the name Andre Maurois.
He studied natural sciences (botany, physiology and biochemistry) under Albert Dastre, great scientific experimenter, himself a student of Claude Bernard.
Đaja gave his final exam in 1905 and, mentored by Dastre, received a PhD on 23 July 1909 with the thesis in physiology Study on ferments of glycosides and carbohydrates in mollusks and crustaceans.

During his studying, he also had several jobs.
In 1904, he became the youngest foreign correspondent of Serbian daily Politika.
Only 20 years old, he became recently established newspaper's reporter from Paris and first foreign correspondent in general.
He also worked for a while at National Museum of Natural History with Paul van Tieghem, before spending five years at Marine station in Roscoff, Brittany.
Starting in 1906, he worked there with Yves Delage and Albert Dastre, beginning his career as a researcher.
Đaja finished elementary and high school in Belgrade. After graduating at First Belgrade Gymnasium in 1902, he moved back to France, spending one year as a student at the Lycée Pierre-Corneille at Rouen. He studied philosophy under Émile Chartier. In 1903 he enrolled at the Sorbonne, where one of his fellow students and best friends was Émile Herzog, later famous French author under the name Andre Maurois. He studied natural sciences (botany, physiology and biochemistry) under Albert Dastre, great scientific experimenter, himself a student of Claude Bernard. Đaja gave his final exam in 1905 and, mentored by Dastre, received a PhD on 23 July 1909 with the thesis in physiology Study on ferments of glycosides and carbohydrates in mollusks and crustaceans.
During his studying, he also had several jobs. In 1904, he became the youngest foreign correspondent of Serbian daily Politika. Only 20 years old, he became recently established newspaper's reporter from Paris and first foreign correspondent in general. He also worked for a while at National Museum of Natural History with Paul van Tieghem, before spending five years at Marine station in Roscoff, Brittany. Starting in 1906, he worked there with Yves Delage and Albert Dastre, beginning his career as a researcher.
Ivan Đaja