Aim: Vaginal versus intramuscular progesterone for prevention of preterm labour in high risk pregnancy. Materials and methods: 150 have received either vaginal or intramuscular progesterone as per obstetrician choice. women with Singleton pregnancy, Gestational age 20-36 weeks POG best determined according to LMP or early fetal ultrasonography, History of preterm, premature rupture of membrane before 37 weeks, History of spontaneous mid trimester loss of last pregnancy And Vaginal bleeding after 14 weeks in present pregnancy were included in this study. Vaginal group: 75 patients received 200mg vaginal tablet twice daily. Intramuscular group: 75 patients received 250mg of intramuscular hydroxy progesterone caproate once weekly injection. Results: The mean age of the patient in the vaginal group was 28.21±3.45 years and in the intramuscular group was 28.20±3.68years. Mean gestational age (in weeks) at start of progesterone in take was 21.48±1.90 in vaginal group and 21.67±1.80 in intramuscular group. Differences between both the groups was not statistically significant (p=0.538). The above table depicts, that mean gestational age (in weeks) at the time of delivery was 35.88±3.21 in vaginal group and 35.72±3.49 in intramuscular group. It was seen that 55 cases who delivered preterm had a mean cervical length of 2.53±0.38 cm and 95 cases who delivered at term had a mean cervical length of 3.07±0.26 cm and this difference was statistically significant (p≤0.001). 53 (70.7%) babies in the vaginal group and 55 (73.3%) babies in the intramuscular group had no admission to NICU while 22 (29.3%) babies in vaginal group and 20 (26.7%) in intramuscular group were admitted in NICU. Conclusion: We conclude that vaginal progesterone and intramuscular progesterone can be equally useful in the prevention of preterm delivery. Vaginal progesterone in dose of 200 mg twice a day was as effective as 250mg/week of intramuscular progesterone in reducing preterm birth.