A multicentre comparative clinical study of CLa implant and Sino-implant was carried out at 100 subcentres in 11 provinces, and α total of 19673 subjects were recruited. Two-year follow-up has been finished. The follow-up rate at the end of two years was 94.29%. Two-year cumulative continuation rate per 100 women for Sino-implant(89.93) was significantly higher than that for CLa implant (88.89). Two-year cumulative pregnancy rates per 100 women were 0.0462(CLa implant) and 0.281(Sino-implant) respectively, there was statistically significant difference between them. No ectopic pregnancy was recorded among CLa implant users and three ectopic pregnancies were reported among Sino-implant users,resulting in an ectopic pregnancy rate of 0.163 per 1000 women-years. The incidence of side effects appeared to diminish with time. The major side-effects were the menstrual disturbances, which accounted for more than 90% of the total sideeffects, and the incidence of frequent menstruation, irregular bleeding and spotting was higher than that of infrequent/scanty menstruation and amenorrhea. Use of CLa implant had higher incidence of amenorrhea and infrequent/scanty menstruation than that of Sino-implant. During two-year follow-up, the number of discontinuation due to menstrual problems contributed 78% of the total number of discontinuation; two year menstrual-related cumulative discontinuation rates were 8.96 per 100 women for CLa implant and 7.84 for Sino-implant, there wasAddress coryespoll(lol,c’c toe D]’ Fang ac juan, Shanghai Institute of Planned Pal.cnthood Research, 2140 Xit, “I’u BOilal. Shanghai. 200032, China. Tel/F..f 86--021 64171432 E ..ill SIPPRms. STN. sh. C Nstatistically significant difference(P< 0.01). Two year study shows that the two types of implant are similar to Norplant in the incidence of side-effects and contraceptive efficacy as well as two year continuation rates. A multicentre comparative clinical study of CLa implant and Sino-implant was carried out at 100 subcentres in 11 provinces, and α total of 19,663 subjects were recruited. Two-year follow-up has been finished. The follow-up rate at the end of Two-year cumulative continuation rate per 100 women for Sino-implant (89.93) was significantly higher than that for CLa implant (88.89). Two-year cumulative pregnancy rates per 100 women were 0.0462 (CLa implant) and 0.281 (Sino-implant) respectively, there was statistically significant difference between them. No ectopic pregnancy was recorded among CLa implant users and three ectopic pregnancies were reported among Sino-implant users, resulting in an ectopic pregnancy rate of 0.163 per 1000 women-years The incidence of side effects were to diminish with time. The major side-effects were the menstrual disturbances, which accounted for more than 90% of the total side effects, and the incidence of frequent menstruation, irregul ar bleeding and spotting was higher than that of infrequent / scanty menstruation and amenorrhea. Use of CLa implant had higher incidence of amenorrhea and infrequent / scanty menstruation than that of Sino-implant. During two-year follow-up, the number of discontinuation due to menstrual problems contributed 78% of the total number of discontinuation; two year menstrual-related cumulative discontinuation rates were 8.96 per 100 women for CLa implant and 7.84 for Sino-implant, there was Addressory coryespoll (lol, c’c toe D] ’Fang ac juan, Shanghai Institute of Planned Pal. Counseling Research, 2140 Xit, ”I’u BOilal. Shanghai. 200032, China. Tel / F..f 86--021 64171432 E ..ill SIPPRms. STN. sh. C Two year study shows that the two types of implant are similar to Norplant in the incidence of side-effects and contraceptive efficacy as well as two year continuation rates.