We handle in this paper three dominating clique problems, namely, the decision problem to detect whether a graph has a dominating clique and two optimization versions asking to compute a maximum- and a minimum-size dominating clique of a graph G, if G has a dominating clique. For the three problems we propose exact moderately exponential algorithms with worst-case running time upper bounds improving those by Kratsch and Liedloff [D. Kratsch, M. Liedloff, An exact algorithm for the minimum dominating clique problem, Theoret. Comput. Sci. 385 (1–3) (2007) 226–240]. We then study the three problems in sparse and dense graphs also providing improved running time upper bounds. Finally, we propose some exponential time approximation algorithms for the optimization versions.