This article investigates grocery store format patronage behaviour of elderly shoppers. The aim is to identify specific antecedents of this consumer group and investigate heterogeneity between segments in terms of their patronage behaviour. Based on a literature review we set up a conceptual model that proposes effects between the perception of store attributes, satisfaction, patronage intention and the share of visits. We test the model using a survey of more than 400 supermarket patrons aged 60 and over who live in a highly concentrated urban retail environment. Variance based structural equation modelling reveals that the product range and the price-value ratio have the most considerable impact on patronage behaviour of supermarkets. Nevertheless, response based segmentation identifies unobserved heterogeneity in the overall modelling results. Unlike demographic characteristics of the respondents the variables 'availability of a car' and 'problems in walking longer distances' explain the heterogeneity of the results between segments where significantly different impacts of accessibility and price-value ratio on patronage behaviour can be identified.