Purpose To assess cardiac motion-induced signal loss in diffusion-weighted magnetic resonance imaging (DWI) of the liver using dynamic DWI. Materials and methods Three volunteers underwent dynamic coronal DWI of the liver under breathholding, in the diastolic (DWI diast ) or systolic (DWI syst ) cardiac phase, and with motion probing gradients (MPGs) in phase encoding (P, left-right), frequency encoding (M, superior-inferior), or slice select (S, anterior-posterior) direction. Liver-to-background contrasts (LBCs) of DWI syst were compared to those of DWI diast , for both the left and right liver lobes, using nonparametric tests. Signal decrease ratios (SDRs) were calculated as (1 (median 3.35) were significantly lower (P < 0.0001) than those of DWI diast (median 4.84). In the right liver lobe, LBCs of DWI syst (median 4.17) were also significantly lower (P < 0.0001) than those of DWI diast (median 5.35). SDRs of the left and right liver lobes were 25.5% and 17.3%, respectively. In DWI syst , the significantly lowest (P < 0.05) LBCs were observed in the M direction (left liver lobe) and P direction (right liver lobe) of MPGs. Conclusion Signal intensity of both liver lobes are affected by cardiac motion in DWI. In the left liver lobe, signal loss especially occurs in the superior-inferior direction of MPGs, whereas in the right lobe, signal loss especially occurs in the left-right direction of MPGs.