Abstract. Let K be a set of k vertices. The k-distance of K is the sum of all distances between pairs of vertices of K. The (k,l)-eccentricity of a set of l vertices L is the maximum k-distance over all sets K, such that L is a subset of K and |K|=k. Finally, the (k,l)-radius of a graph, rad_k,l(G), is its minimum (k,l)-eccentricity.

The notion of (k,l)-radius generalizes the notions of radius (rad(G)=rad_2,l(G)), the diameter (diam(G)=rad_2,0(G)), k-diameter (which equals rad_k,0(G)) and the distance of a graph (which is rad_|V(G)|,0(G)). In this note we determine (k,l)-radius of Petersen graph for all possible values of k and l.