Objectives: Non-adherence (NA) by adolescents receiving cancer treatment is believed to be a major problem. However, adequate measures of NA have not been developed. The purpose of this study was to (1) assess the internal reliability of a new scale reflecting low-risk NA behaviours, (2) examine whether the scores on this scale were associated with high-risk NA behaviours and (3) assess the relationship between NA behaviours and patient attitudes towards stopping treatment. Methods: Thirty-three patients (16-24 years) with solid tumours reported on their previous adherence with treatment. Low-risk NA behaviours were assessed on a 0-40 scale derived from the sum of 10 items. High-risk NA behaviours and attitudes towards stopping treatment were assessed by questions with yes/no response options. Results: Internal reliability of the low-risk NA scale was α=0.73. Patients not seeking help for pyrexia had higher total low-risk NA scores than those who sought help (mean 7.4, SD 5.3 vs mean 3.5, SD 3.6, t=2.1, p=0.03). There was also a trend for individuals who ignored pyrexia to be more likely to have contemplated stopping treatment than those who sought medical assistance (Fisher's Exact=0.09). Conclusions: A scale reflecting low-risk NA behaviour had good internal reliability and was associated with not seeking help when pyrexic. Ignoring a temperature was also associated with contemplating stopping treatment. We are now conducting a prospective study using the measure to assess validity against a range of information regarding NA. Copyright © 2009 John Wiley & Sons, Ltd.