There is varying reports. I do believe particularly during this time the Genovese and Gambino Families were in between 300-500 members.

One thing this research has taught me : something we all already know but when its laid out in front of you, it gives a different perspective. The Luciano/Genovese organization's manpower, capabilities and shear wealth, was unfathomable. I have read that several members (not including the Hierarchy or Caporegime) were millionaire status. Thats a whole different level of success IMO. no wonder they still stand today