Abstract Aim The aim of this study is to validate high-resolution endovaginal T2- and diffusion-weighted MRI measurements (tumour size, volume and length of uninvolved cervical canal) against histology in patients undergoing trachelectomy. Patients/interventions 55 consecutive patients 25–44 years with cervical cancer being considered for trachelectomy were prospectively assessed with endovaginal T2-W and diffusion-weighted MRI. Two independent observers blinded to histology recorded maximum tumour dimension, volume and distance from the superior aspect of the tumour to the internal os. Following trachelectomy, pathologist-outlined tumour sections were photographed with a set scale and similar measurements were recorded. Results Fifteen of 45 patients subsequently treated with fertility-sparing surgery had residual tumour (median histological volume: 0.28 cm3 , IQR = 0.14–1.06 cm3 ). Sensitivity, specificity, positive and negative predictive values for detecting tumour: Observer1: 86.7%, 80.0%, 68.4%, and 92.3%, respectively; Observer2: 86.7%, 90.0%, 81.0%, and 93.1%, respectively. Size and volume correlated between observers (r = 0.96, 0.84, respectively, p < 0.0001). Size correlated between each observer and histology (observer 1 r = 0.91, p < 0.0001; observer 2 r = 0.93, p < 0.0001), volume did not (observer 1: r = 0.08, p = 0.6; observer 2: r = 0.21, p = 0.16); however, differences between observer measurements and histology were not significant (size p = 0.09, volume p = 0.15). Differences between MRI and histology estimates of endocervical canal length were not significant (p = 0.1 both observers). Conclusion In subcentimetre cervical cancers, endovaginal MRI correlates with pathology and is invaluable in assessing patients for fertility-sparing surgery.