For a compact Riemann surface X of genus g > 1, Hom(π 1 (X), U(p, 1))/ U(p, 1) is the moduli space of flat U(p, 1)connections on X. There is an integer invariant, τ , the Toledo invariant associated with each element in Hom(π 1 (X), U(p, 1))/ U(p, 1). If q = 1, then −2(g − 1) ≤ τ ≤ 2(g − 1). This paper shows that Hom(π 1 (X), U(p, 1))/ U(p, 1) has one connected component corresponding to each τ ∈ 2Z with −2(g − 1) ≤ τ ≤ 2(g − 1). Therefore the total number of connected components is 2(g − 1) + 1.