Objectives: This study examines the characteristics of studies that Health Canada uses to grant full marketing authorization for products given a conditional approval between January 1, 1998 and June 30, 2017. Design: Cohort study. Data sources: Journal articles listing drugs that fulfilled their conditions and received full marketing authorization, Notice of Compliance database, Notice of Compliance with conditions web site, Qualifying Notices listing required confirmatory studies, clinicaltrials.gov, PubMed, Embase, companies making products being analyzed, journal articles resulting from confirmatory studies. Interventions: None Primary and secondary outcome measures: Characteristics of studies - study design (randomized controlled trials, observational), primary outcome used (clinical, surrogate), blinding, number of patients in studies, patient median age, number of men and women. Results: Eleven companies confirmed 36 publications for 19 products (21 indications). Twenty-nine out of the 36 studies were randomized controlled trials (RCTs) but only 10 stated if they were blinded. Twenty used surrogate outcomes. The median age of patients was 56 (interquartile range (IQR) 44, 61). The median number of men per study/trial was 184 (IQR 58, 514) versus women - 141 (IQR 46, 263). Conclusions: Postmarket studies required by Health Canada had more rigorous methodology than those required by either the Food and Drug Administration or the European Medicines Agency. There were still deficiencies in these studies. The absence of blinding in the majority of RCTs may introduce bias in their results. The use of surrogate outcomes especially in oncology trials means that improvements in survival are not available. The relatively young age of patients, even for products for cancer, means that predicting how the elderly will respond is often unknown. The almost universal finding that men outnumbered number women may make it hard to differentiate responses by sex. These results raise potential concerns about the quality of evidence that Health Canada accepts.