This work discusses design issues of microturbines for combined energy sources based on microhydropower plants for the heads H≤20 m and the flow rates Q ≤1.20 m3/s. It is proposed to optimize microturbines. The main approaches to the formulated problem are described, optimization algorithm is analyzed exemplifying its embodiments for separate elements of microhydroturbines. The proposed approach has been verified. Experimental results of microhydroturbine optimization for simulated combined energy source based on microhydropower plant with the available head H =1.1 m, flow rates Q ≤0.021 m3/s and rotation frequency of electric generator n = 1000 rpm have been presented. On the basis of numeric simulation, the hydraulic efficiency of hydroturbine has been increased by 5.4% as a consequence of the proposed approaches.