Introduction The Canadian Perinatal Network (CPN) is a national database focused on threatened very pre-term birth. Women with one or more conditions most commonly associated with very pre-term birth are included if admitted to a participating tertiary perinatal unit at 22 weeks and 0 days to 28 weeks and 6 days. Methods At BC Women’s Hospital and Health Centre, we compared traditional paper-based ward logs and a search of the Canadian Institute for Health Information (CIHI) electronic database of inpatient discharges to identify patients. Results The study identified 244 women potentially eligible for inclusion in the CPN admitted between April and December 2007. Of the 155 eligible women entered into the CPN database, each method identified a similar number of unique records (142 and 147) not ascertained by the other: 10 (6.4%) by CIHI search and 5 (3.2%) by ward log review. However, CIHI search achieved these results after reviewing fewer records (206 vs. 223) in less time (0.67 vs. 13.6 hours for ward logs). Conclusion Either method is appropriate for identification of potential research subjects using gestational age criteria. Although electronic methods are less time-consuming, they cannot be performed until after the patient is discharged and records and charts are reviewed. Each method’s advantages and disadvantages will dictate use for a specific project.