This study investigated ability and skill mappings as determinants of employee retention in civil service commission in Bayelsa and Cross-Rivers States, Nigeria. Cross-sectional survey design was employed and structured questionnaire was the major data collection instrument. The study population comprised 389 employees of civil service commission and a sample of 197 was obtained via probabilistic sample size determination formulae. Questionnaire was administered on 197 respondents who are employees of civil service commission, out of which 187 were fully retrieved. Data obtained were analyzed using descriptive, diagnostic and inferential statistical methods. The multiple regression results showed that ability mapping (t-value = 7.17; Prob. = 0.000 < 0.05) and skill mapping (t-value = 6.44; Prob. = 0.000 < 0.05) significantly positively influence employee retention. On this note, it was recommended that management should see skill and ability mappings as imperative strategic human resource management mechanisms of enhancing retention of employees. Hence, during employee recruitment, selection and placement, ability and skill of employees should be sternly emphasized. Also, Nigerian civil service commission should formulate policies targeted at enhancing skill and ability mappings of employees via training and development programmes. This study contributes to knowledge by using competency Ice-Berg model in describing the ability and skill mappings and employee retention nexus and established that ability and skill mappings significantly influence the retention rate of employees in Nigerian civil service commission.