Even though Peltesohn proved that a cyclic (v, 3, 1)-design exists if and only if v ≡ 1, 3 (mod 6) as early as 1939, the problem of determining the spectrum of cyclic (v, k, 1)designs with k > 3 is far from being settled, even for k = 4. This paper shows that a cyclic (v, 4, 1)-design exists if and only if v ≡ 1, 4 (mod 12) and v ∈ {16, 25, 28}.