They both mean endeavoring to find out more about a subject, but are different in their purpose and methods. - 조사하다: investigate. Involves ordinary activities of surveying, gathering, verifying, and collating facts. - 연구하다: research deeply. Investigate and study to expand knowledge or utility, employing technical methods. * 정부는 이 회사의 세무 관계 부정을 조사했다. => The government investigated this company's tax related infractions. * 줄기 세포의 실용화를 위한 많은 연구가 진행되고 있다. => Numerous researches are being conducted for practical application of stem cells. * 환경 변화를 연구하는 과학자들은 북극 빙하의 상태를 조사한다. => Scientists researching environmental changes survey the glaciers of the North Pole.

연구하다 (study, research) ex)study the structure of human body 조사하다 (investigate,probe) ex) The FBI has been called in to investigate