The paper presents results of experimental dependability evaluation of the Phoenix-RTOS operating system. Experiments are conducted using a self-developed testing environment and a kernel fault injector. Dependability evaluation is the last stage of a system development process. Results will be used in the future research to propose enhanced error detection techniques embedded into the operating system kernel. Categories and Subject Descriptors D.4.5 [Operating Systems]: Reliability—dependability evaluation General Terms Reliability Keywords operating system dependability evaluation