The increasing amount of the clinical research conducted in the primary health care has enabled extending research beyond traditional settings, but this transfer has implied some trade‐offs. Health care professionals who conduct research with trusted patients require assuming the ethical standards of research and communication skills to enable patients' autonomy and freedom of choice. This study aims to measure the opinions of health professionals and patients on issues of communication in clinical research.

A cross‐sectional study with health care professionals and patients from primary health care centres in Barcelona (Spain). Each group completed a similar self‐administered questionnaire. A Rasch model was fitted to data. After examination of goodness‐of‐fit, differences between groups were compared using analysis of variance, and patients' measures were calibrated to professionals' measures to compare overall mean measures.

Professionals and patients found the ethical attitudes most difficult to endorse related to trust in clinical researchers and conflicts of interest. Patients' perceptions of professional ethical behaviour were significantly lower than professionals'. Different item functioning between nurses and family doctors was found in the item on seeking ethical collaboration when collaborating in clinical research. Effective knowledge of ethical norms was associated with greater perceived ethical values in clinical research and confidence in health care professionals among patients.

Differences in the views of the communication process between patients and professionals could alert research boards, health care institutions and researchers to the need for greater transparency, trust and ethical instruction when patients are involved in clinical research.