Background <p>Artificial Intelligence (AI) is rapidly transforming healthcare delivery worldwide. The adoption of AI among healthcare professionals in Nigeria, its patterns of use, and associated factors are emerging issues that need to be explored. This study aimed to assess the prevalence, patterns, and determinants of AI use among healthcare professionals in Lagos State, Nigeria.</p> Methods <p>A descriptive cross-sectional study was conducted among 415 healthcare professionals across 14 public health facilities in Lagos, representing primary, secondary, and tertiary levels of care. Data were collected using a structured, self-administered questionnaire and analysed using descriptive statistics, chi-square tests, and binary logistic regression.</p> Results <p>Although only 19.8% had received formal AI training, 86.5% reported using AI and 51.3% used it specifically for professional duties. The most common professional application was diagnostic support, including clinical reasoning, interpretation of laboratory and radiological findings, and medication-interaction checks. AI use in professional duties was significantly associated with educational level (<i>p</i> = 0.042); postgraduate-qualified professionals were twice as likely to use AI as those with only basic healthcare degrees (OR = 2.07, <i>p</i> = 0.014). Key barriers included privacy concerns, algorithmic distrust, and limited formal training.</p> Conclusion <p>Despite low formal training, use of AI-related digital tools was common among healthcare professionals in public health facilities in Lagos, primarily supporting diagnostic reasoning and clinical documentation. These findings highlight the need for structured AI literacy programs and institutional governance frameworks to support safe and equitable AI integration in Nigeria’s health system.</p>