This report is a study of the fossil freshwater diatoms from two deposits on the Kenai Peninsula, Alaska. These deposits, averaging from 2 to 6 feet in thickness, crop out along the sea cliffs bordering Cook Inlet, some 5½ to 11½ miles northward of the village of Kenai. They contain a flora encompassing 344 species, varieties and forms of diatoms, including 21 new taxa. The deposits overlie some 13 feet of glacial outwash with a carbon-14 age between 8,000 and 14,000 years B.P.