The Victorian Perinatal Data Collection Unit (PDCU) maintains a Birth Defects Register (BDR), including data on terminations of pregnancy for birth defects before 20 weeks. This study aimed to validate the completeness of reporting, and accuracy of diagnoses provided by hospitals on these terminations. From 1995-1999, 13 hospitals notified 321 terminations to the PDCU. An additional 41 cases were found through this study. For matched cases (n=273), 199 (73%) had comparable diagnoses, 21 (8%) had different and 53 (19%) had additional diagnoses. Discrepancies arose because of problems with correct identification of relevant cases and lack of understanding of the importance of including all information on multiple birth defects.