Meconium peritonitis (MP) is a sterile chemical peritonitis resulting from intestinal perforation in utero. We present two cases of preterm neonates weighing 2580 g and 3100 g respectively, in whom fetal meconium peritonitis was diagnosed by antenatal ultrasonography (US) and magnetic resonance imaging (MRI). Both patients required surgery. As the literature suggests, newborn surgery for meconium peritonitis is sometimes very difficult owing to severe adhesions and bleeding. The aim of these case reports is to underline that close collaboration between neonatologists and pediatric surgeons is essential for the timely diagnosis and prompt management of MP, but also to reveal the benefit of primary anastomosis (PA) for MP as well as to demonstrate the importance of the imagistic techniques in diagnosing and managing MP, both before and after birth.