Aim Early cancer diagnosis is necessary to improve survival rates. The aim of this study was to assess the outcome and cost of the childhood cancer training programme amongst healthcare workers. Design This was a prospective pre–post study design, using questionnaires for pre‐ and post‐training testing. The warning signs of childhood cancer were used as the main teaching content to improve recognition and early diagnosis. Methods Pre‐training and post‐training knowledge, as well as attitude questionnaires, was administered at the beginning and at the end of each training workshop. Paired samples t test and chi‐square were used to compare the change in knowledge and differences between groups. Results The overall percentage knowledge score increased from 51%–85% (p < .001). The doctors had a better knowledge score than the nurses in the pre‐test (70% versus 50%, p = .008), but there was no significant difference in the post‐test scores. The cost of training was €25.06 per healthcare worker. Conclusion We recommend similar training programmes in public health to improve early diagnosis of childhood cancer.