The ultrasonic backscatter difference technique analyzes the power difference (in dB) between two gated regions of a backscatter signal and is being used to detect changes in bone caused by osteoporosis. The current study investigates correlations with bone density for these parameters determined from clinical ultrasound data. Ultrasonic backscatter images and signals were acquired from the hip and two vertebral bodies of human subjects using a 2.5 MHz phased-array transducer. Three backscatter parameters- normalized mean, slope, and intercept of the backscatter difference- were determined from the power difference between two gated regions of the signal. All three parameters were analyzed for 25 different gate choices. X-ray bone mineral density data for each subject were acquired for the three anatomical regions. Significant linear correlations (p<0.05) were found for all three ultrasonic parameters for at least one choice of gate parameters. R values ranged from to 0.38 to 0.63. For the first time, backscatter difference parameters measured in vivo have been shown to correlate with bone density. The correlation may depend on the gated regions of the backscatter signal chosen for analysis. [Funding: NIH/NIAMS R15AR066900.]