Objective: To assess whether organisational culture influences the fidelity of implementation of the Integrated Chronic Disease Management (ICDM) model at primary healthcare (PHC) clinics. Design: A cross-sectional study. Setting: The ICDM model was introduced in South African clinics to strengthen delivery of care and improve clinical outcomes for patients with chronic conditions, but the determinants of its implementation have not been assessed. Participants: The abbreviated Denison organisational culture (DOC) survey tool was administered to 90 staff members to assess three cultural traits: involvement, consistency and adaptability of six PHC clinics in Dr. Kenneth Kaunda and West Rand (WR) health districts. Primary and secondary outcome measures: Each cultural trait has three indices with five items, giving a total of 45 items. The items were scored on a Likert scale ranging from one (strongly disagree) to five (strongly agree), and mean scores were calculated for each item, cultural traits and indices. Descriptive statistics were used to describe participants and clinics, and Pearson correlation coefficient to asses association between fidelity and culture. Results: Participants’ mean age was 38.8 (SD=10.35) years, and 54.4% (49/90) were nurses. The overall mean score for the DOC was 3.63 (SD=0.58). The involvement (team orientation, empowerment and capability development) cultural trait had the highest (3.71; SD=0.72) mean score, followed by adaptability (external focus) (3.62; SD=0.56) and consistency (3.56; SD=0.63). There were no statistically significant differences in cultural scores between PHC clinics. However, culture scores for all three traits were significantly higher in WR (involvement 3.39 vs 3.84, p=0.011; adaptability 3.40 vs 3.73, p=0.007; consistency 3.34 vs 3.68, p=0.034). Conclusion: Leadership intervention is required to purposefully enhance adaptability and consistency cultural traits of clinics to enhance the ICDM model’s principles of coordinated, integrated, patient-centred care.