The viscosities of aqueous solutions of several, α, β and γ-amino acids at three different pH's have been measured at temperatures between 30–40 °C in the concentration range 0.005 to 0.1 molai, and the B-coefficients have been calculated using the equation η/η0 = 1 + Bc. The corresponding activation energies for viscous flow have been calculated with the help of the Feakins, Freemantle and Lawrence equation. The S-coefficients for all the amino acids at the three pH's follow the sequence B(inH2o) > B(in NaOH) > B(in HCL) over tne above temperature range. The gradual decrement of B-coefficients from water to HCl has been discussed in terms of decreasing electric field of the ions concerned. From the temperature coefficient of B it has been inferred that the simultaneous influence of polar and non polar parts is responsible for the extra structure enhancement by the γ-amino acids in aqueous solution. © 1982, Akademische Verlagsgesellschaft, Wiesbaden