We placed 24 pairs of adult San Marcos salamanders in small flow-through aquaria with rocks and aquatic moss. Some aquaria had clear marbles within tubes through which water upwelled into each aquarium. Seven clutches (eggs per clutch: mean  =  34.7; range  =  2 to 73) were produced during a 9-month period. Overall hatching success was 29.6%. One breeding pair reproduced 3 times (eggs per clutch: mean  =  44; range  =  27 to 59) at an average of 64-day intervals during a 191-day period. Once mature, a single female potentially could produce 176 eggs per year in captivity.