To describe and validate a simultaneous proton density fat-fraction (PDFF) imaging and water-specific T1 mapping (T1(Water) ) approach for the liver (PROFIT1 ) with mapping and low sensitivity to calibration or inhomogeneity. A multiecho gradient-echo sequence, with and without saturation preparation, was designed for simultaneous imaging of liver PDFF, , and T1(Water) (three slices in ~13seconds). Chemical-shift-encoded MRI processing yielded fat-water separated images and maps. T1(Water) calculation utilized saturation and nonsaturation-recovery water-separated images. Several variable flip angle schemes across k-space (increasing flip angles in sequential RF pulses) were evaluated for minimization of T1 weighting, to reduce the dependence of T1(Water) and PDFF (reduced flip angle dependence). T1(Water) accuracy was validated in mixed fat-water phantoms, with various PDFF and T1 values (3T). In vivo application was illustrated in five volunteers and five patients with nonalcoholic fatty liver disease (PDFF, T1(Water) , ). A sin3 (θ) flip angle pattern (0<θ<π/2 over k-space) yielded the largest PROFIT1 signal yield with negligible dependence for both T1(Water) and PDFF. Mixed fat-water phantom experiments illustrated excellent agreement between PROFIT1 and gold-standard spectroscopic evaluation of PDFF and T1(Water) (<1% T1 error). In vivo PDFF, T1(Water) , and maps illustrated independence of the PROFIT1 values from inhomogeneity and significant differences between volunteers and patients with nonalcoholic fatty liver disease for T1(Water) (927±56ms vs. 1033±23ms; P<.05) and PDFF (2.0%±0.8% vs. 13.4%±5.0%, P<.05). was similar between groups. The PROFIT1 pulse sequence provides fast simultaneous quantification of PDFF, T1(Water) , and with minimal sensitivity to miscalibration or inhomogeneity.