Glomeruli from normal and diseased human kidneys were explanted in tissue culture chambers and were studied by phase-contrast microscopy and time-lapse cinematography. Observation from the time of explantation to several months of culture revealed that glomerular cells are capable of prolonged survival and various activities in vitro. Glomerular cells retained in culture some of the morphological and functional characteristics described in fixed preparations and revealed, in addition, dynamic aspects peculiar to living cells. Cells lining glomerular capillary loops exhibited pulsatile movements which caused glomeruli to contract and expand rhythmically. Persistent, rhythmic and synchronous contractions of entire glomeruli were dependent upon the presence of viable, grossly intact pulsatile cells in all capillary loops. This activity was impaired or lost through injury or death of cells.