The variability of the parameters of the signal of the pulse the radial artery in a number of diseases assessed, in particular, the early stage of arterial hypertension in childhood and adolescence, mitral valve prolapse, lung cancer. The ratios of the vibrational components of vegetative regulation for various types of diseases revealed. It is shown that the degree of variability depends, in part, on the parameter of the pulse signal studied. In particular, in the detection of arterial hypertension, the greatest variability and diagnostic significance occur in the study of the dicrotic wave of the pulse signal. In this case, the same indicators significantly exceeded when examining the duration of the pulse signal — an analogue of the heart rhythm. The received estimations of variation of parameters of a pulse signal allow form purposefully informative signs at carrying out of differential diagnostics of diseases.