Pylephlebitis, which is a type of septic thrombophlebitis of the portal vein, is a rare and life-threatening complication that commonly occurs following appendicitis. However, nonspecific abdominal complaints and fever can impede the diagnosis of pylephlebitis. Timely use of appropriate antibiotics and anticoagulants is paramount for treating this condition. We present a case of pylephlebitis and septic shock caused by acute nonperforated appendicitis. A 32-year-old man presented with migratory right lower abdominal pain. Blood cultures showed the presence of Escherichia coli. Blood test results showed increased bilirubin concentrations and coagulation factor abnormalities. A computed tomographic abdominal scan showed that the portal vein had a widened intrinsic diameter. After intensive care treatment with antibiotics, antishock therapy, anticoagulants, and other supportive treatments, the infection was monitored, the abdominal pain disappeared, and the jaundice subsided. Laparoscopic appendectomy was performed. Histopathology showed acute suppurative appendicitis, and no abnormalities were observed during the follow-up period after discharge. A multidisciplinary approach is mandatory for the decision-making process in the presence of pylephlebitis caused by appendicitis to obtain a correct diagnosis and prompt treatment. Similarly, the timing of appendectomy is important for minimizing intra- and postoperative complications.