The src family of tyrosine kinases (srcFK) are important upstream regulators of Rho‐kinase mediated Ca2+‐sensitization and constriction in rat pulmonary artery (RPA). We hypothesise that srcFK act through modulation of the activity of RhoA. Cytosolic to membrane translocation of RhoA in RPA smooth muscle cells, visualised using over‐expressed green fluorescent protein‐tagged RhoA was used as an indication of RhoA activation. Translocation was stimulated by prostaglandin‐F2α (20 μM), the superoxide generating quinone LY83583 (10 μM), and the RhoA activator calpeptin (0.02 U/ml). This translocation, following all three types of stimulus, was prevented by prior incubation with the srcFK antagonist PP2 (10 μM). Calpeptin also constricted myograph‐mounted RPA, and this constriction was inhibited by PP2. srcFK are likely to be activating RhoA through phosphorylation of one or more of the many proteins that directly activate or inhibit RhoA, namely guanine nucleotide exchange factors (RhoGEF), GTPase activating proteins (RhoGAP), and guanine nucleotide dissociation inhibitors (RhoGDI). We used RT‐PCR to confirm endogenous expression of p115‐RhoGEF, PDZ‐RhoGEF, LARG, Vsm‐RhoGEF, SmgGDS, vav‐3, p73‐RhoGAP, RhoGDI‐1 and RhoGDI‐2 in RPA. The GEF Vav‐2 was not expressed. Our data suggests that srcFK may be contributing to Ca2+‐sensitization and constriction of RPA through activation of RhoA.