Wnt proteins have been implicated in regulating growth and pattern formation in a variety of tissues during embryonic development. We previously identified Frzb‐1, a gene which encodes a secreted protein with homology in the ligand binding domain to the Wnt receptor Frizzled, but lacking the domain encoding the putative seven transmembrane segments. Frzb‐1 has recently been shown to bind to Wnt proteins in vitro, and to inhibit the activity of Xenopus Wnt‐8 in vivo. We report now that mFrzb‐1 and Wnt transcripts display both complementary and overlapping expression patterns at multiple sites throughout embryonic development. By Northern analysis, the expression of mFrzb‐1 in the developing mouse embryo is greatest from 10.5 to 12.5 days postcoitum (dpc). In the early embryo, mFrzb‐1 is expressed in the primitive streak, presomitic mesoderm, somites, and brain. Later, mFrzb‐1 exhibits sharp boundaries of expression in the limb bud, branchial arches, facial mesenchyme, and in cartilaginous elements of the appendicular skeleton. We conclude from these experiments that Frzb‐1is expressed at a time and location to modulate the action of Wnt family members during development of the limbs and central nervous system. Dev. Dyn. 1998;212:364–372. © 1998 Wiley‐Liss, Inc.