Callose consists mostly of (1,3)-beta-D-glucan and is synthesised in many plant tissues during growth and development, where it is believed to play a fundamental role in cell plate formation during cell division. Callose deposition also represents an important response to pathogen attack, wounding and to various abiotic stresses. Here, the transcription patterns of members of the callose synthase gene family from barley (Hordeum vulgare) were defined. Thus, fragments of six barley (1,3)-beta-D-glucan synthase-like (GSL) cDNAs were obtained by PCR amplification using primers designed to barley expressed sequence tag (EST) sequences. The HvGSL genes, designated HvGSL2 to HvGSL7, were mapped to individual loci that were distributed across the barley genome on chromosomes 3H, 4H, 6H and 7H. The HvGSL1 gene has been isolated and characterised previously. Transcript levels for all the genes were analysed by quantitative real-time PCR in a range of barley tissues and organs, at various developmental stages. High levels of transcript for many of the HvGSL genes were detected in endosperm during the early stages of grain development, when cellularisation of the endosperm was occurring and it is likely that many of the genes participate in this process. Transcripts of HvGSL1 and HvGSL5 mRNAs were significantly more abundant than other GSL mRNAs in the roots of young seedlings, while HvGSL7 mRNA was detected at relatively high levels along the length of two week old shoots.