Background: Populations are ageing and therefore non-communicable diseases are becoming leading causes of global morbidity, which need to be the focus of primary care services and training. Some older patients are uncomfortable with general practitioner (GP) trainees managing their chronic conditions, reducing clinical experience opportunities for trainees. This Australian cross-sectional study explored the factors underlying patients' attitudes to trainees in an agency theory framework. Methods: Fifty patients aged 60 and over from each of 38 training practices were offered a questionnaire after their consultation. Principal component analysis of the results was undertaken. Factor scores were calculated. Binary logistic modelling was used to identify relationships between participant characteristics, behaviours, attitude items and factor scores. Results: The response rate was 47.9% (n = 911). Three factors were identified: 'Interpersonal Trust' (IPT); 'Institution/system Trust' (ST); and 'Interpersonal Continuity' (IPC). Lower self-rated health (SRH) was associated with higher IPT factor scores (P = 0.023); higher SRH with higher ST scores (P = 0.001); and chronic illness with higher IPC scores (P = 0.005). Higher ST scores were associated with greater comfort with trainees' involvement in chronic care (P < 0.001) and frequency of trainee visits (P < 0.001), while higher IPC scores were negatively associated (P < 0.001 and P = 0.003, respectively). High IPT scores were associated with lower satisfaction with trainee visits (P = 0.001). Discussion: These results indicate that better SRH, via higher institution/ST, is associated with favourable attitudes and attendance with trainees. In addition, chronic illness, via a higher need for IPC, is associated with lower comfort and attendance. These findings are consistent with agency theory, which shows potential as a framework for future interventions and research into older patient-trainee interactions.