Abstract. In 1950 a class of generalized Petersen graphs was introducedby Coxeter and around 1970 popularized by Frucht, Graver and Watkins.The family of I-graphs mentioned in 1988 by Bouwer et al. representsa slight further albeit important generalization of the renowned Petersengraph. We show that each I-graph I(n;j;k) admits a unit-distance rep-resentation in the Euclidean plane. This implies that each generalizedPetersen graph admits a unit-distance representation in the Euclideanplane. In particular, we show that every I-graph I(n;j;k) has an isomor-phic I-graph that admits a unit-distance representation in the Euclideanplane with a n-fold rotational symmetry, with the exception of the fam-ilies I(n;j;j) and I(12m;m;5m), m  1. We also provide unit-distancerepresentations for these graphs. 1. IntroductionI-graphs were introduced in the Foster census [5] and form a natural gen-eralization of the generalized Petersen graphs introduced by Coxeter [8] andnamed by Watkins [26]. This well-known family of graphs has been extensivelystudied [1, 10, 18, 20, 22, 25].Let n3 and j;kbe such that 1 j, k