The L-asparaginase (E. C. 3.5.1.1) enzyme was purified to homogeneity from Pseudomonas aeruginosa 50071 cells that were grown on solid-state fermentation. Different purification steps (including ammonium sulfate fractionation followed by separation on Sephadex G-100 gel filtration and CM-Sephadex C50) were applied to the crude culture filtrate to obtain a pure enzyme preparation. The enzyme was purified 106-fold and showed a final specific activity of 1900 IU/mg with a 43% yield. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDSPAGE) of the purified enzyme revealed it was one peptide chain with M, of 160 kDa. A Lineweaver-Burk analysis showed a K. value of 0.147 mM and of V_(max) 35.7 IU. The enzyme showed maximum activity at pH 9 when incubated at 37˚ for 30 min. The amino acid composition of the purified enzyme was also determined.