Non-immune hydrops fetalis (NIHF) is due to many different causes. Fetal hypomobility has been alluded to as a possible cause. We present a preterm fetus with NIHF secondary to fetal hypomobility. Fetal movements were undetected after the 20th week of gestation. The infant was born 8 weeks later and was edematous, had pleural effusions, and no spontaneous movements. He died on day four of life. Diffuse massive central nervous system (CNS) destruction found on post-mortem examination was thought to be the origin of the hypomobility. As all other causes of NIHF were eliminated, we propose that the NIHF in this infant was due to the hypomobility. This case then gives support to the assertion that fetal hypomobility is another cause of NIHF. The cause of the CNS catastrophy remains unelucidated.