Basement membrane (type IV) collagens are believed to have several roles in development. Southern blot analysis suggests there are only two type IV collagen genes in C. elegans. These collagen genes correspond to the genetic loci emb-9 and let-2. To study the location of EMB-9 and LET-2 we have generated antibodies to the non-collagenous domains of EMB-9 and LET-2. In addition, let-2 is alternatively spliced to produce two transcripts differing in a single exon. One transcript contains exon 9; the other contains exon 10. We have generated antibodies to amino acid sequences specific to exons 9 and 10. All antibodies have been affinity purified and react specifically to their targets based on Western blotting and/or competition experiments.