Abstract: Capital structure has been one of the most controversial issues in the field of finance during past years. There are a number of existing theories and empirical studies observing patterns involved in choosing a capital structure, however until now, there is no universal one. The purpose of the study was to carry out empirical test, to determine the influence of firm specific factors as suggested by various theories on the optimal capital structure of Kenyan insurance firms. The study population involved all the registered insurance firms, the research targeted firms that had a continua’s operation between 2003 and 2012 and the analysis was based on the year-end observations for ten consecutive years.