Abstract: In implementing the large-scale use of blue-green algae as biological fertilizers,a problem has arisentas to the conservation of the algae in a viable state,and at the same time in a condition facilitating transportation.Experiments have been made in drying the algal cultures in an incubator, and also by hot drying air,at temperatures of 35° to 40℃.We found that the dried algal material grew well after inoculating medium HB No.105,even after it had remained from one to six months in the dried condition.Also,that a better growth was obtained when the dried material was first inoculated onto a diluted medium and 2 days later subcultured onto the normal strength medium.