Sonic echo, sonic mobility, dynamic impedance function, and impedance log tests were used to estimate the length, diameter, low-strain stiffness, and existence of defects for two drilled shafts. An overview of the data acquisition, processing, and interpretation procedures for each test is presented. The length measurements agreed well with the design length of one shaft but underestimated the length of the second shaft, possibly because the shaft was socketed into rock. Impedance log tests provided the most accurate diameter measurements that agreed remarkably well with the diameters backcalculated from the volume of concrete. Values of the low-strain axial stiffness were nearly the same for both shafts, but were higher than the stiffnesses observed in the static load tests because of the different strain levels involved in each test.