Paraffin and polyethylene waxes were found to be efficient as controlled delivery systems for six different commercial-grade fertilizers. These fertilizers are monoammonium phosphate, diammonium phosphate, NP, NPK-4, and NPK-14 grades, and granular triple superphosphate fertilizers. Dissolution tests were performed for matrix-type formulations in order to determine. the influence of waxes on the fertilizers release rate. Three different diffusion release formulas were tested for describing the release rate of the different fertilizers. The release times were at least doubled for all of the fertilizers while using either paraffin wax or polyethylene wax. The polyethylene wax gives longer release times than the paraffin wax.