Background: Maternal mortality ratio in Tanzania is 454/100,000 live births where by PPH alone accounts for 25-28% of all maternal death (TDHS, 2010). PPH due to uterine atony accounts for more than 75% of PPH in Tanzania (TDHS, 2010). It is an obstetric emergency that can effectively be prevented by conducting a cheap procedure called Active Management of the Third Stage of Labour (AMTSL). This study aimed at assessing knowledge and skills of midwives in conducting AMTSL for preventing primary PPH and to report barriers to its implementation in Municipal hospitals of Dar es Salaam region in Tanzania. Material and Methods: A comparative cross-sectional within subjects design was conducted at Amana, Mwananyamala and Temeke municipal hospitals of Dar es Salaam region, Tanzania. 87 midwives (30 from Amana 17 from Mwananyamala and 40 from Temeke municipal hospitals) out of all expected (105) who worked in labour and postnatal wards were studied. Data was collected by using questionnaire with four parts (demographic, training, AMTSL knowledge, policy/motivation/barriers information) contained both open and close ended structured questions. Practice of AMTSL was observed on normal vaginal deliveries by using a standard tool developed by Ministry of Health and Social Welfare of Tanzania (MoHSW) in collaboration with Johns Hopkins Program for International Education in Gynecology and Obstetrics (JHPIEGO) in 2010. A satisfactory score in practice and knowledge was 90%+ and 85%+ respectively. A competent midwife on AMTSL had to obtain satisfactory scores in both knowledge and skills (MoHSW, 2010). Data was coded, entered, cleaned and analyzed in SPSS for windows version 15. Chi-square (X2) test and Odds ratio (OR) with 95% confidence interval (CI) were used to define the association of independent and dependent variables. A tool for logistic assessment was developed from the conceptual model that was developed after multinational study conducted in African Region in assessing the practicability of AMTSL. Participation in the study was purely voluntary. vii Results Majority of participated midwives performed well on what are considered the three most important components of AMTSL by ICM/FIGO (2003), (i.e. 10 IU of oxytocin (87.4%), CCT (92%) and uterine massage (72.4%)). But there are 18 steps that comprise a standard AMTSL practice. When considering that standard observation guide and standard questions set on AMTSL, only 10% of participating midwives achieved satisfactory standard scores in both knowledge and skills. Knowledge gave a strong association with being skillful (x2 test, p = 0.01< 0.05). Multivariate regression analysis signified association between place of training and competency level (x2 test , p = 0.02< 0.05), those who learnt AMTSL in midwifery/nursing school then got on job training were more likely to acquire competence on AMTSL than those who got from midwifery school alone, OR =7.143 (1.017,50.188) (adjusted OR = 0.140 (0.020, 0.984). All municipal hospitals had the AMTSL protocol, with enough supply of uterotonics in the previous two consecutive months stored under appropriate temperature. However, lack of on job training and shortage of staff and supplies were reported as major barriers that most midwives suggested were important for more successful AMTSL implementation. Conclusions and Recommendations. AMTSL Trials of Improved Practices (TIPS) and maternal outcomes can be conducted to determine barriers to the use of AMTSL and suggestions from providers on how to improve their practice of AMTSL and maternal health in achieving MDG 5. MoHSW should increased provision of on job training on AMTSL that fits with Tanzanian clinical environment and AMTSL job aids should be used, adapted and disseminated to all health facilities and Provided to pre-service educational programs while creation of ideal work environment (space, staffing, supplies and motivation) should be taken into consideration.