Asparaginase from Helicobacter pylori has been cloned and expressed in E. coli cells. Optimization of culturing and expression conditions allowed achieving stable synthesis of catalytically active asparaginase amounting up to 6% of total bacterial protein. A method developed for enzyme purification included a single chromatographic stage and provided more than sixty percent yield of homogeneous asparaginase. Specific asparaginase and glutaminase activities were estimated to 92 and 8,310-3 ME/mg respectively. Due to low glutaminase specificity HpA may be employed as a non-toxic drug for leukemia treatment.