To assess FOCUS diffusion-weighted imaging (DWI) for prostate cancer assessment, 30 consecutive biopsy-proven patients underwent both FOCUS and conventional DWI. Sensitivity and specificity was not significantly different between sequences but inter-observer agreement improved from moderate to substantial when using FOCUS. There was significantly lower SNR and CNR for FOCUS on b-value images, but similar CNR on ADC maps. Mean ADC values were significantly lower using FOCUS and both sequences showed excellent discrimination between malignant and benign prostate with no statistical difference. FOCUS DWI improves agreement between observers of varying experience while maintaining diagnostic accuracy despite lower SNR and CNR.