Aim: To assess pathological and radiological prognostic factors for cancers detected by screening within a multi-centre RCT trial of mammographic screening of younger women. Method: The survival of 232 women with screen detected invasive cancer was ascertained. Data on invasive cancer size, histological grade, nodal status, vascular invasion, mammographic spiculation, comedo calcification and mammographic background were assessed. Kaplan-Meier and Cox proportional hazards methods were used to examine survival. Results: Univariate analysis indicated that women with cancers with the following features had poorer survival; =30 mm, histologically grade 3, heavily node positive (4 or more positive nodes), vascular invasion positive and displaying mammographic comedo calcification. In a multivariate model survival remained poorer in women with four or more nodes positive (HR 8.36, 95% CI 2.31, 30.17) and in those with comedo calcification (HR 3.00,95% CI 1.13, 7.99). Conclusion: Nodal status and the presence of mammographic comedo calcification have independent prognostic significance in young women with screen detected cancer.