Non-immune hydrops fetalis (NIHF) is a symptom of other underlying complications during pregnancy, such as lymphatic dysplasia and cardiovascular, hematologic, and chromosomal disorders. The incidence of spontaneous resolution of NIHF is 5.7% and mostly occurs in cases of known etiology. Here, the authors report the case of a 29-year-old healthy primipara admitted to the hospital at 21 weeks’ gestation due to pleural and peritoneal effusion, and edema of subcutaneous tissue of the fetus. Diagnostic examinations failed to reveal the etiology of NIHF. Due to an increase in hydrops, thoracentesis, and several cordocenteses with administration of albumins were performed. At 32 weeks, hydrops resolved completely with no recurrence. The baby, without any signs of hydrops, was delivered by cesarean section at 38 weeks. Diagnosing NIHF cases is difficult and requires many examinations to evaluate the etiology of the disorder, its management, and prognosis. NIHF resolving spontaneously without any consequences for child’s development rarely occurs.