Experimental results are presented for thin high resistivity concentrator silicon solar cells which use a back-side point-contact geometry. Cells of 130 and 233 µm thickness were fabricated and characterized. The thin cells were found to have efficiencies greater than 22 percent for incident solar intensities of 3 to 30 W/cm2(30-300 "suns"). Efficiency peaked at 23 percent at 11 W/cm2measured at 22-25°C. Strategies for obtaining higher efficiencies with this solar cell design are discussed.