Chikahiko Koizumi (小泉 親彦, Koizumi Chikahiko^?, September 9, 1884 – September 13, 1945) was a Japanese military physician.

After graduating Tokyo Imperial University, he joined the Japanese Medical Corps.

Koizumi became Army Surgeon General of the Imperial Japanese Army in 1934.

He was the Minister of Health and Welfare from 1941 to 1944 under the Konoe and Tōjō cabinet.

After the war, he came under suspicion of war crimes as a minister when the war broke. But Koizumi refused the investigation and committed suicide by Seppuku.