Introduction: Idiopathic granulomatous mastitis is a benign chronic inflammatory disease of the breast. Lactation is considered as one of the most important risk factors. We investigated the effect of lactation on the findings of contrast-enhanced and diffusionweighted magnetic resonance imaging (DW-MRI) in IGM and aimed to identify the most observed findings. Methods: Contrast-enhancedand DW-MRI of 40 patients with lactation history in the last 5 years and 35 patients reporting no lactation history had been reevaluated retrospectively. Morphological features, enhancement pattern and kinetics of lesions were assessed based on BI-RADS. The presence of diffusion restriction was evaluated and apparent diffusion coefficient (ADC) values were obtained. MRI findings with lactation status were compared. Results: Non-mass contrast enhancement (p<0.02), cluster pattern (p<0.008) and fistula formation (p<0.035) were more frequently seen in patients with a lactation history than in patients reporting no lactation history. On MRI most common observed findings were concomittantly mass and non-mass contrast enhancement and abscess formation. Diffusion restriction was present in all of the lesions and the mean ADC values were 0.93 ± 0.25 x 10-3 mm 2 /s. Conclusion: Lactation status increases the incidence of non-mass contrast enhancement, cluster pattern and fistula formation on MRI.