Sewage sludge is an example of waste considered as biomass. The utilization of sewage sludge is more often realized through combustion, which simultaneously constitutes the recovery of energy from a renewable source. However, the obtained ash requires neutralization. An alternative method for landfilling of sewage sludge ash is its conversion into synthetic zeolites. One of them is Zeolite P. The study shows the results of thesynthesis of zeolite P from sewage sludge ash by chemical conversion. The conversion of sewage sludge ash was conducted at the activationtemperatures of 60°C and 90°C, crystallization temperatures of 60°C and 90°C, crystallization time of 72 hours and the SSA:NaOH ratio of 1:1.4. The research of sewage sludge ashes after zeolitization included the observation of changes of ash particles surface, the identification of crystalized phases, cation exchange capacity (CEC) and specific surface area. The optimalsynthesis conditions for zeolite P are the activation and crystallization temperatures of 90°C. CEC of modified sewage sludge ashes is greater than CEC of sewage sludge ash. The presented method of sewage sludge ash conversion allows to obtain a usable material.