The quality of official perinatal mortality statistics in a geographical and administratively well defined region (Asturias, Spain) is studied in a five years period (1986-90). The official figures were compared with those collected, retrospectively, from multiple hospital sources. Under-registration of perinatal death was 35% (45.5% of fetal death and 22.5% of early neonatal death, these occurred in the first 24 hours). Validity of mentioned statistics is discussed.