Kadamjay District (Кадамжай районы; Кадамжайский район) is a district (raion) in Batken Province, in south-western Kyrgyzstan.: The district capital lies at Pulgon. Its population in 2005 was approximately 30,000. The largest town of the district, the town of Kadamjay, is located between the cities of Khaidarkan (Aidarken) and Kyzyl-Kiya.
The district is thought to have the second largest mercury-antimony deposit in the world. Kadamjay Antimony Factory is one of the biggest factories in Kyrgyzstan. Khaidarkan Mercury Plant, built in 1942, was reported, as of 2005, to produce 300 to 600 metric tons of mercury per year.
Ak-Su is the river which passes through Kadamjay. Jiydelik lake is a favorite picnic spot.