The question of why variation is maintained in personality traits is an evolutionary puzzle. According to the condition-dependence hypothesis, such traits depend on condition, which limits the behavioural choices available to individuals. Because condition is affected by many genes, it can effectively be manipulated by inbreeding, which exposes the effects of deleterious recessive mutations. Here, I compared two personality traits, boldness and tendency to explore, of male guppies (Poecilia reticulata) from first-generation inbred and outbred treatments. Boldness in guppies is associated with increased sexual attractiveness, and is thus expected to affect fitness. Therefore, I hypothesised that the personality traits would be negatively affected by inbreeding. However, the results indicated that inbred guppies did not differ in either personality trait from their outbred counterparts. This finding suggests that mechanisms other than condition-dependence are maintaining personality variation in the guppy.