Abstract. We present two different representations of (1, 1)-knots and study some connections between them. The first representation is algebraic: every (1, 1)-knot is represented by an element of the pure mapping class group of the twice punctured torus PMCG 2 (T ). Moreover, there is a surjective map from the kernel of the natural homomorphism Ω : PMCG 2 (T ) → MCG(T ) ∼ = SL(2, Z), which is a free group of rank two, to the class of all (1, 1)-knots in a fixed lens space. The second representation is parametric: every (1, 1)-knot can be represented by a 4-tuple (a, b, c, r) of integer parameters such that a, b, c ≥ 0 and r ∈ Z 2a+b+c . The strict connection of this representation with the class of Dunwoody manifolds is illustrated. The above representations are explicitly obtained in some interesting cases, including two-bridge knots and torus knots.