On-shelf availability and out-of-stocks remain important issues for retailers, particularly clothing retailers. This chapter reports on the state-of-the-art research in this domain and investigates a UK clothing retailer’s efforts at improving availability through two in-depth case studies of different clothing product categories. The studies were shaped around a conceptual model using a framework for food or grocery retailing developed by ECR Europe to improve availability, customer satisfaction and productivity, but which necessitates antecedents of human resources, infrastructure and collaboration. The research found that the retailer’s actual in-store availability of less than 80% across the categories studied was 15% lower than the food or grocery sector and indeed 11% lower than its own information databases. Several of the necessary antecedents were absent at the retailer and hence progress in improving availability will require first addressing the antecedents.