Intensity of plumage colour may advertise individual condition, health and parasite resistance of birds. Although numerous studies confirmed such function of ornaments in songbirds, still very little is known about signalling properties of colour feathers in woodpeckers. We test whether the size and colour of a red cap displayed by both male and female Middle Spotted Woodpeckers are related to mass and length of tarsus, wing, tail and beak. We found that body mass was correlated with cap width and brightness in woodpeckers of both sexes. At the same time body mass affected reproductive success of individuals. This suggests that both cap width and brightness has the potential to signal individual condition in the studied species.