Promyelocytic leukemia HL‐60 cells promoted by PMA to differentiate along the monocyte pathway adhere to tissue culture plates. To explore the regulation of adhesion molecules in cells promoted to differentiate, the expression and secretion of osteopontin (OPN) and expression of associated cell surface receptors, CD44 and integrin subunits α_v, β₃, β₁, were examined. Results were as follows: (1) PMA induced OPN mRNA and OPN secretion into media; (2) untreated cells expressed β₁ and CD44 mRNA, and PMA induced α_v and β₃ mRNA and increased β₁ and CD44 mRNA expression; (3) PMA increased levels of α_v, β₃, β₁ and CD44 protein on the cell surface; and (4) retinoic acid, which promotes granulocytic differentiation of HL‐60 cells, did not affect OPN, α_v, β₃, β₁, or CD44 mRNA or protein expression. These data suggest that induction of OPN and associated receptors may play a role during monocytic differentiation of HL‐60 cells. J. Cell. Physiol. 175:229–237, 1998. © 1998 Wiley‐Liss, Inc.