Otolith microstructure analysis was used to validate microincrement deposition rate and to determine daily growth rates of young-of-the-year (YOY) Baringo tilapia, Oreochromis niloticus baringoensis. Micro-increment formation was validated as daily by correlating the number of circuli on otoliths with the known age of cultured fish. For wild young-of-the-year fish collected from Lake Baringo, Kenya, in August and October 2007 length was positively correlated with the age of fish (total length (mm) = 0.1187 age (/day) 1.1344 (r² = 0.97); standard length (mm) = 0.0964 age (/day) 0.7082 (r² = 0.97)) and growth rate was subsequently estimated at 0.12 cm/day.