Подольская губерния
In 1913 he returned to Ukraine where he found the job as head of the Bureau of Statistics in Balta uyezd of Podolia Governorate. In 1914 Ostapenko was transferred to Kharkiv where he headed the Bureau of Statistics for the Mining Industry of Sloboda Ukraine. Later he returned to Kyiv where he worked as a private-docent in the Kyiv Commercial Institute until 1917.