The pay delays influence on reserves are very important problem for insurance companies. We consider two particular examples of models that attempt to deal with pay delays in insurance, in this work. The first model provides one explanation for underwriting cycle; the second indicates the effects of delays. We were reckoned reserves by chain – ladder method, multiplicity method, and separation method. We had made pay delays modeling program with generated data; this program should made easier to estimate pay delays influence on reserves. We have done simulation with different damage distribution and come to some conclusion like: the insurance premium was enough for the insurance company, because the reserves were positive. There are no big differences in reserves results, calculated by different methods.