Objectives: To determine the impact of the diagnostic test method (clinical, diagnostic imaging, or diagnostic laparoscopy) of endometriosis on the individual’s sense of control over their disease and their perceived access to social supports. Design: Retrospective cohort study. Setting: International. Population: 1,634 people aged 18-55 who had received a diagnosis of endometriosis. Methods: This study reports on data collected by the validated Endometriosis Health Profile-30 (EHP-30) section of a larger survey conducted between May and July 2020. Participants were recruited by social media platforms. Scores on the dimensions of interest were analysed with diagnostic method as the variable of interest. Diagnostic method proportionality was also assessed as a secondary outcome by geographical region. Main Outcome Measures: Scores on the dimensions of control and powerlessness and social support on the EHP-30. Results: There was a difference between control and powerlessness scores for patients that received a diagnosis via imaging (ultrasound/magnetic resonance imaging) versus clinical diagnosis (P=0.049). However, this did not reach significance when co-variates were controlled for (P=0.054). No other comparisons between diagnostic method and EHP-30 scores demonstrated a difference. There was a statistically significant (P<0.0001) difference in the rate of utilization of the various diagnostic imaging techniques between geographical regions with diagnostic imaging being relatively uncommon and surgery being the most common method of diagnosis. Conclusions: The diagnostic method of endometriosis does not appear to have a clinically significant impact on an individual’s sense of control over their disease nor their access to social supports.