Title: Group actions on Spheres with rank one isotropy Authors: Ian Hambleton and Erg{\" u}n Yal{\c c}{\i}n Status: submitted. Address1: Department of Mathematics, McMaster University, Hamilton, Ontario L8S 4K1, Canada Email1: hambleton@mcmaster.ca Address2: Department of Mathematics, Bilkent University, 06800 Bilkent, Ankara, Turkey Email2: yalcine@fen.bilkent.edu.tr Abstract: Let $G$ be a rank two finite group, and let $\cH$ denote the family of all rank one $p$-subgroups of $G$, for which $\rk_p(G)=2$. We show that a rank two finite group $G$ which satisfies certain group-theoretic conditions admits a finite $G$-CW-complex $X\simeq S^n$ with isotropy in $\cH$, whose fixed sets are homotopy spheres.