The purpose of this work was to link the coalescence behaviour of bubbles in aqueous electrolyte solutions with the character of gas-liquid beds generated in bubble column reactors and with corresponding values of bubble bed voidage. The experimental programme, performed with the set of nine inorganic salts, included determination of the bubble coalescence frequency in a coalescence cell and measurement of gas holdup in a sieve tray bubble column reactor of 0.14 m I.D. Values of the transition concentration, corresponding to the switch from the complete coalescence to virtually total coalescence suppression, were evaluated for all electrolytes studied from respective concentration dependences of bubble coalescence frequency and the gas holdup values were measured in solutions of respective electrolytes on both sides of these transition concentrations. The absolute increase of bubble bed voidage due to the presence of electrolytes was found to be independent of the type of electrolyte and varied only with the mode of primary gas dispersion. The appropriate limiting dependences of bubble bed voidage on superficial gas velocity, corresponding to respective bubbling regimes were, for all electrolytes studied, achieved at concentrations close to the transition concentrations of respective electrolytes, while further increase of salt concentration had an almost negligible effect on gas holdup values. The influence of electrolytes on the character of bubble beds and on appropriate values of bubble bed voidage was very strong in the homogeneous and transition bubbling regimes, while in heterogeneous bubble beds, it was largely overshadowed by the predominant effect of macro-scale turbulence.