This study aimed to investigate the effects of walking surfaces and shoe features on gait variables associated with balance control and the risk of slips and trips in 10 young and 26 older adults. A systematic approach was adopted in which the features of a standard, Oxford-type shoe were individually modified. Subjects walked along a level (control), irregular, and wet walkway in eight randomised shoe conditions (standard, elevated heel, soft sole, hard sole, high-collar, flared sole, bevelled heel and tread sole). Walking velocity, step length, step width, cadence, double-support time, heel horizontal velocity and shoe-floor angle at heel contact, and toe clearance at mid-swing were measured. Older people exhibited a more conservative walking pattern, especially on the irregular and wet surfaces. Compared to the standard shoes, the elevated heel shoes elicited increased double-support time, heel horizontal velocity at heel strike and toe clearance. On the wet surface, the soft sole shoes led to shorter steps and a flatter foot landing, gait adaptations which are associated with perceptions of shoe/surface slipperiness. Increasing collar height led to greater double-support time and step width. The results indicate that shoes with elevated heels or soft soles impair walking stability in older people, especially on wet floors, and that high-collar shoes of medium sole hardness provide optimal stability on level dry, irregular and wet floors.