Childhood undernutrition coupled with poor feeding practices continues to be public health problems in many parts of the world and efforts to address them remain elusive. We tested the hypothesis that women who are exposed to radio health/nutrition education will demonstrate greater nutrition and health knowledge, positive attitudes towards preventive health and better dietary diversity practices for improved child growth. We used a two-arm, quasi-experimental, non-equivalent comparison group design with pre- and post-test observations to evaluate the intervention. The study population comprised 712 mothers with children aged 6–36 months who were randomly selected from five intervention districts and one comparison district in Northern Ghana. Difference-in-difference (DID) analysis was performed to assess study outcomes. After 12-month implementation of intervention activities, the minimum dietary diversity and the minimum acceptable diet improved significantly (DID 9⋅7 percentage points, P 0⋅014 and DID 12⋅1 percentage points, P 0⋅001, respectively) in the intervention study group, compared with the comparison group. Mothers in the intervention communities had a nutrition-related knowledge, attitudes and practices score that was significantly higher than their colleagues in the comparison communities (DID 0⋅646, P < 0⋅001). The intervention did not have significant effects on the nutritional status as measured by height-for-age Z-score or weight-for-height Z-score. The data provide evidence that health and nutrition education using radio drama significantly increased health-/nutrition-related knowledge but had little effect on nutritional status.