The use of biopolymer of poly (3-hydroxybutyrate) [(P(3HB)] as a matrix of urea slow release fertilizer has been carried out. The microencapsulation of urea was conducted using the solvent evaporation method. The ratio of urea-P(3HB) for formula 1, 2, and 3 were of 1-1, 1-2, and 1-3 respectively. Microcapsules were evaluated by Scanning Electron Microscope (SEM), Fourier Transform Infra Red (FTIR) spectroscopy, amount of urea in microcapsule, particle size distribution, release test, and kinetic release of active substance. Results showed that the biopolymer P(3HB) could be used as a matrix of urea slow release fertilizer. There was no chemical interaction between urea and P(3HB) during the process of microcapsules formation. The amount of urea in microcapsules in Formula 1, 2, and 3 were detected of 41.39%, 28.89%, and 24.47% respectively. The microcapsules formed the spherical shape with particle size distribution of urea in microcapsules was ranged from 11.4 to 607 μm. it is also observed that the release kinetics model of the active substance (urea) followed the Korsemeyer-Peppas equation. Statistical assay of One Way ANOVA showed that the use of P(3HB) affect the efficiency of release test significantly (p<0.05) which means that an increase in the concentration of P(3HB ) as matrix could reduce the release of urea from the microcapsules.