Crystals of different morphology (needle-, rod-tetragonal- and wedge-shaped) were grown from the same solution of ribosome and in the same drop using 10-15% 2-methyl-2,4-pentanediol as a precipitant. The crystals appeared in 5-48 h. Observations of the kinetics of crystal appearance lead to the conclusion that higher supersaturation of ribosome solution produces needle-shaped crystals, while the tetragonal-rod- and the wedge-shaped crystals grow at lower supersaturation. The ribosome packing in the crystals was characterized by electron microscopy (EM). An analysis of EM ultrathin sections indicates that the unit cells, with a high degree of probability, are the same in the needle-shaped and other morphology crystals. The data obtained suggest that adjusting supersaturation of the crystallization solution may convert needle-shaped to more useful morphologies.