People with type 2 diabetes are often prescribed multiple medicines which can be difficult to manage. Nonadherence to medicines can be intentional (e.g. active decision) or unintentional (e.g. forgetting). The objective of this study was to measure intentional and unintentional non-adherence to differing numbers of medicines prescribed in type 2 diabetes. A cross sectional survey using the Morisky medication adherence scale (with intentional and unintentional non-adherence subscales) was completed by 480 people prescribed oral antidiabetic drugs (OADs), antihypertensive agents and statins. A within-subject analysis of variance (ANOVA) showed that intentional non-adherence did not vary between OADs, anti-hypertensives and statins. Intentional non-adherence to statins significantly increased when the number of medicines prescribed was included as a between-subjects variable (p<0.05). Another within-subject ANOVA on unintentional non-adherence found a significant difference between OADs, anti-hypertensives and statins; unintentional non-adherence to OADs was significantly higher (p<0.05). When the number of medicines was added as a between-subject variable unintentional non-adherence was associated with higher numbers of medicines. This study shows the difference between intentional and unintentional non-adherence behaviours, and the effect that varying numbers of medicines can have on these behaviours. Br J Diabetes Vasc Dis 2010;X:XXX-XXX.