At the Club’s foundation in 1901, there were 236 members. Rules 27 of the 1901 Book of Rules refers to the ‘proprietor’. At the start, the Club was proprietary, owned by Boustead & Ridley who had built and owned Mombasa Club and from whom the premises was later leased.
The earliest membership list in the Club records is that dated 1903 which lists 256 members. In that list were more than a few notables: Sir John Ainsworth, Provincial Commissioner, Sir George Whitehouse, Chief Engineer of the Railway, (Sir) Frederick Jackson, later Lieutenant-Governor, Governor of Uganda and renowned ornithologist, Sir Harry Johnston, British Commissioner for Uganda, Sir Charles Eliot, British Commissioner for East Africa and Richard Meinertzhagen, the Soldier, adventurer and naturalist who achieved some notoriety in the time he spent in East Africa. Whatever else Meinertzhagen may have been, he was a fine naturalist and discovered the Giant Forest Hog, not previously known to science.
From the original 236, numbers grew steadily; over the years growth has been gradual rather than rapid. In 1933 concern was voiced over declining membership and a proposal that the Entrance Fee be varied or suspended by the Committee was carried, but only after lengthy and heated discussion. It was said that ‘a virile young country needed a virile Club and that to maintain that virility a regular flow of young members was necessary’. Some of the speakers were worried about ‘undesirable members’ while others pointed out that the purpose of a balloting Committee was to prevent that happening. Junior membership was introduced in 1934, limited to those between ages of 21 and 28 and who would on reaching 28 be eligible for full membership without further ballot, although the age rules changed from time to time. The current rule 31(a) provides for elected junior membership, which ceases on the attainment of 25 years.
The war years saw temporary increases in military membership. After the Second World War (1939-45), numbers picked up and amenities were extended but work was limited by a building control Committee, set up by the government in 1946.
By 1967, membership was 3,229, of which 1,882 were full members. It remained fairly constant around the 3,000 mark, although there was a drop to 2,810 in 1974.

A high point was reached in 1980 with 4,116 members. Since then, numbers have gradually declined; a much higher entrance fee and higher subscriptions probably account for this. Membership by mid-2000 was 2,247 of which 1,533 were full members.