Abstract The study was included (66) undiagnosed aborted women at different stage of pregnancy compared with (40) healthy subjects as control groups . A high significant increase (P:Q.05) in The activity of alanine aminopeptidase in urine of single &recurrent abortion first & second trimesters were shown (5.3+0.33) (10.E5*0.05)U/L qand (14.5+0.39) (22.71A.72)U/l respectively compared to healthy subject (5i!A.24') (5.4+0.48) and (4.3+0.295)U/L for normal pregnant (1" trimesters) , (2 nd trimesters) and non pregnant women . AAP was purified from urine of aborted women by gel-filtration using sephadex (G-50) and two isoenzymes of AAP I,II were separated fiom urine samples by using DEAE-cellulos .