OBJECTIVE: In the UK, General Practitioners and Practice Managers are key to enabling health information exchange (typically referred to as 'data sharing'). This study aimed to survey GPs and PMs for familiarity, engagement with and perceptions of patient data sharing. METHODS: Cross-sectional survey. All 107 general practices in England's second largest Clinical Commissioning Group, Cambridgeshire & Peterborough CCG. Descriptive statistics; hierarchical logistic regression; thematic analysis. RESULTS: 405 (64%) responses were received - from 338 (62%) GPs and 67 (71%) PMs. Familiarity and engagement were highest for local frail elderly and end of life care projects (>76% had used). The greatest difference in use concerned the now suspended national care.data initiative: PMs had odds of reporting use 75 times higher than GP partners (95% CI 27-211). Patient confusion was the most pronounced challenge and improved coordination the most pronounced expected benefit. Frequency of discussions with patients varied with IT competence (OR 4.2 for most competent users relative to least, 95% CI 1.7-10.7) and clinical system (OR 0.3, 95% CI 0.1-0.5). Patient reservations were reported more frequently by respondents who rated their IT competence as highest (OR 3.3, 95% CI 1.5-7.6), perceived more data sharing challenges (OR for a 1-point increase in challenges perception score 3.4, 95% CI 2.1-5.6) and by PMs (relative to GP partners, OR 18.0, 95% CI 7.9-41.3). CONCLUSIONS: Familiarity with and use of data sharing projects was high among GPs and PMs. Both their individual and organisational characteristics were associated with the reported frequency of discussions and patients' responses. Improved awareness of the impact of provider characteristics and attitudes on patients' decisions about data sharing may enhance the equity and autonomy of those decisions.