Understanding medical staff’s prescription behaviors helps improve the quality of prescriptions and the rationality of medication use. Although factors affecting the prescribing decisions were discussed in various studies worldwide, limited knowledge of these issues has been reported in Vietnam. This paper aims to examine factors that influence prescribing behavior concerning medical staff’s demographics and characteristic differences.

Quantitative descriptive cross-sectional study, using adapted questionnaire consisting of 27 factors divided into 9 factor categories, was conducted with medical staff in Mekong Delta during June–July, 2019. Rasch analysis was performed to assess the questionnaire psychometric properties. Descriptive analysis, parametric tests and non-parametric tests were utilized to address the study objectives.

A total of 201 participants completed the questionnaire. A majority of participants (>90%) agreed that their own decision to prescribe a drug was influenced by several factors such as drug safety and efficacy (92.5%), patient history (92.0%), patient income (92.0%) and patient disease status (91.0%). There were significant age differences in influences on prescribing decision. Medical staff aged under 30 appreciated the role of pharmacists higher than whose aged 31–40 (P-value = 0.010) and over 40 (P-value = 0.013). Additionally, they were more concerned with ‘patient characteristics’ including patient request, expectations, and disease status when making prescribing decisions compared with whose aged over 40 (P-value = 0.005).

The study revealed various factors influencing medical staff prescription decision-making processes. These findings could be useful for pharmaceutical companies in Vietnam in developing marketing strategies, and for policy-makers in timely improvement of prescription quality.