We have utilised the constant photocurrent method (CPM) and steady state photoconductivity measurements to investigate the creation and annealing kinetics of light induced metastable defects, and their effect on photoconductivity, in a set of good quality a-Si1-xCx:H (x less than or equal to 0.11) at room temperature. The annealing activation energy distribution for the alloys was deduced using the method proposed by Hata and Wagner [J. App. Phys. 72 (1992) 2857]. A narrow Gaussian distribution of annealing activation energies, peaking at about 1 eV, accounts for the observed annealing behaviour for the unalloyed sample. For the alloys, the peak positions of the Gaussian distributions shift to 1.1 eV, with increasing carbon content. The relationship between the inverse mobility-lifetime product, determined from steady state photoconductivity measurements, and the light induced metastable defect density during the creation and annealing cycles was also investigated for these alloys. (C) 2003 Elsevier Science B.V. All rights reserved.