The synthesis and pharmacological activity of partial retro‐inverso modified rat atrial natriuretic factor (rANF) analogs is described. The route to these compounds utilized a combination of solution and solid‐phase methods. The analogs prepared all contain a reversed amide bond (Ψ[NHCO]) at the Ser25 to Phe26 linkage. This bond has been suggested to play a key role in the metabolic inactivation of ANF. The analogs are of comparable potency to the endogenous peptide rANF1‐28 in binding to cultured rat vascular smooth muscle cells, in relaxing serotonin contracted rabbit aortic rings, and as natriuretic/diuretic agents in anesthetized rats. None of the peptides has an extended duration of action in vivo.