Literature on the quality and completeness of data and documentation in investigator-initiated research studies is scarce. We carried out a study to compare the quality of data and documentation in an investigator-initiated trial (IIT) with those in an industry-sponsored study. We retrospectively studied the archived data pertaining to 42 patients enrolled in two trials, 14 patients in an industry-sponsored study and 28 randomly selected patients from an IIT. Trial-related documents were examined and scored for the completeness of the acquisition of data and for storage as per a pre-formulated checklist. Weighted scores were given for each point on the checklist proportional to its relative importance in the data documentation process. A global score and sub-scores for specific modules were given for each subject. The scores in the two studies were compared using the Mann Whitney U test. The total score for general documents was similar in the IIT (14/14, 100%) and the sponsored study (24/25, 96%). The mean summary global score obtained for study-specific documents (maximum possible score, 32) in the IIT (27.1; 95% CI 26.4-27.8) was also not significantly different from that in the sponsored study (27.9; 95% CI 26.7-29.1; p=0.1291). Thus, investigatorinitiated studies carried out by independent researchers in highvolume academic centres, even without active data monitoring and formal audits, appear to adhere to the high standards laid out in the International Conference on Harmonisation-Good Clinical Practices guidelines, ensuring accuracy and completeness in data documentation and archival.