Background: The digitalization of health care has accelerated the adoption of mobile health (mHealth) apps in general and family medicine in Portugal. These tools may support chronic disease management and clinical decision-making. However, limited high-quality scientific evidence and the absence of a national framework for certification and quality standards create uncertainty about their safe integration into clinical practice. Objective: This study aimed to characterize mHealth app use among general and family medicine residents and physicians in Portugal. It also examined factors influencing app selection, barriers to adoption, and clinicians’ perceptions regarding the integration of AI into clinical practice. Methods: An observational, cross-sectional, quantitative study was conducted using an online survey developed with LimeSurvey. The survey was distributed to residents and physicians registered with the (Portuguese Medical Association) who were in active clinical practice. Data were analyzed using descriptive statistics, with absolute and relative frequencies reported. Results: The final sample included 141 participants (n=104, 73.8% female; n=37, 26.2% male). Most clinicians were aware of mHealth apps (138/141, 97.9%), and 85.1% (120/141) reported using them in clinical practice. Among 120 users, 87.5% (n=105) regularly used 2 to 5 apps. A total of 69 unique apps were identified; the 13 most cited accounted for 77.4% (246/318) of all mentions, including Tonic, UpToDate, Cardio4all, and PEM Móvel. Apps were mainly used during clinical consultations (111/120, 92.5%). The most frequent factors influencing app choice were ease of use (114/120, 95.0%) and evidence-based clinical effectiveness (79/120, 65.8%). Reported barriers included lack of knowledge about available apps (117/139, 84.2%) and the absence of national evaluation standards (66/139, 47.5%). Among nonusers (n=21), the main structural barrier was poor integration with clinical information systems (n=15, 71.4%). Regarding AI, 56.0% (79/141) reported awareness of AI-integrated apps, mainly Tonic and ChatGPT. The same proportion considered AI use beneficial, especially for clinical decision support (114/141, 80.9%) and administrative automation (88/141, 62.4%). Key concerns included ethics, data security, and privacy (105/141, 74.5%) and limited interoperability (94/141, 66.7%). Conclusions: mHealth app adoption in Portugal is high but fragmented and largely driven by personal initiative (98/218, 45.0%) and informal recommendations, with limited institutional guidance. Tonic was the only app identified by respondents as reporting compliance with ISO 13485 (medical software quality), ISO/IEC 42001 (AI management systems), and UEMS-EACCME clinical accreditation. Most clinicians perceive national regulatory guidance as insufficient (73/139, 52.5%). Future progress requires the urgent development of a national framework for the curation and recommendation of mHealth apps aligned with international assessment frameworks such as DiGA ( [Digital Health Applications], Germany) and DTAC (England), increased digital health training, and improved interoperability with clinical systems to ensure safe, effective, and equitable use in primary health care.