In thispapel; the reduction of inherent ambiguities in StructurefromMotion(SW)using inertialdata isaddressed. First, we show that the translation-rotation ambiguity inS'from a noisy $ow field computed from twoframes can be completely eliminated by using noisefree inertial rate data. Secondly, we show that the admissible solution space for SfM from noisy feature correspondences can be reduced by using inertial data.