Bitter gourd (Momordica charantia L.) seeds is known to have efficacy in treating skin diseases, one of which is acne. This study aimed to determine the potency of antibacterial activity, minimum inhibitory concentration (MIC) and equality with comparator. The extraction process was carried out by maceration method using ethanol 96%, then fractionation was performed by using liquid-liquid extraction. The antibacterial activity of extract and fractions of bitter gourd seed against Propionibacterium acnes were done by agar diffusion method. The results showed that the extract and other fractions of bitter gourd seeds gave antibacterial activity against Propionibacterium acnes. The extract and three fractions of bitter gourd seeds inhibited the growth of Propionibacterium acnes at concentrations of 40%, 50% and 60%. The value of MIC of the extract was 30% with an 8,9 mm inhibit zone. At concentration of 40%, the fraction of ethyl acetate of bitter gourd seeds gave the highest activity in inhibiting Propionibacterium acnes compared to extract and other fractions. When it is compared with clindamycin as comparison, 1 mg of bitter gourd seed extract is equivalent to 0,80 μg clindamycin.