Pyomyoma (suppurative leiomyoma) is a rare but serious complication of uterine leiomyomas. Although the management of leiomyomas during pregnancy is usually expectant, prompt surgical intervention is mandatory for pyomyoma. We present a case of pyomyoma with peritonitis that necessitated myomectomy at 21 weeks of gestation in a 28-year-old nullipara in which the pregnancy continued to successful delivery at 37 weeks of gestation. Perinatal and neonatal outcomes in pregnancies complicated with pyomyoma may be improved by prompt surgical intervention even in the early second trimester. A brief review of the literature regarding pyomyoma associated with pregnancy is also described.