Purpose: We aimed to compare apparent diffusion coefficient (ADC) values among magnetic resonance imaging (MRI) scanners from different vendors. Materials and Methods: We used a custom-made phantom solution consisting of distilled water, 0.9% NaCl, 25% NaCl, and shampoo for diffusion-weighted MRI (DW-MRI) examinations. DW-MRI was performed with similar sequence parameters using six different 1.5 Tesla MR scanners (scanners A-F). ADC maps were automatically constructed for all DW-MR images (b factors of 0 and 1000 s/mm2). ADC measurements were performed using regions of interest and seven different software programs, including four different postprocessing workstations, two different picture archiving and communication systems, and operator console software for each MR scanner. Results: The ADC values generated by scanners A and F were higher and those of scanner B were lower than those generated by the other scanners (P = 0.002). The intravendor difference in the ADC values averaged from scanners D, E, and F was statistically significant (P < 0.001). The difference between the ADC values obtained by scanners C and E was not statistically different (P = 0.15). Conclusion: ADC values may differ among different MRI systems used for DW-MRI. Thus, the MRI vendor should be considered when using DW-MRI in a clinical setting. © Turkish Society of Radiology 2013.