This record linkage study aims to examine the coding concordance of delivery outcome and discharge status between the New South Wales (NSW) Midwives Data Collection (MDC) and Admitted Patients Data Collection (APDC) as well as factors that contribute to hospital births not being recorded in the APDC. Births recorded in the APDC and MDC datasets for the calendar year 2005 were used for analysis. Births registered in the NSW Registry of Births Deaths and Marriages for the same period were used as validation. Descriptive analysis was used to examine coding concordance between the APDC and MDC datasets for matched records, and logistic regression analyses were used to identify factors associated with hospital births not being included in the APDC. A total of 90,585 unique births were recorded in the MDC for the calendar year 2005. A total of 79,173 confirmed hospital births were matched to corresponding records in the APDC; 2,249 (3%) confirmed hospital births were not found in the APDC. For unmatched records, logistic regression analyses showed that the level of obstetric hospital in which babies were born was a significant factor associated with information not being recorded in the APDC. As compared with local, small isolated, and small metropolitan hospitals (Levels 1 to 3 hospitals), larger tertiary hospitals (Levels 4 to 6) and private hospitals had decreased odds of hospital births not being recorded in the APDC. For matched records, 95% and 99% of records were found to be coded consistently between the APDC and MDC datasets for outcome of delivery and discharge status respectively. With a high level of coding concordance between the APDC and MDC datasets and only a small percentage of hospital births not being recorded in the APDC, the obstetrics subset of the APDC dataset was found to be of good quality.