C-C motif chemokine ligand 2 (CCL2), also called monocyte chemoattractant protein-1 (MCP-1) is a key β-chemokine involved in the migration of monocytes and macrophages, playing a significant role in the inflammatory responses in the airways. We aimed to assess the serum levels of MCP-1/CCL2 in a pilot cross-sectional study of Bulgarian children with bronchial asthma (BA) and cystic fibrosis (CF). Forty-two children were recruited to the study as follows: twenty with BA, twelve with CF and ten healthy children. Serum MCP-1/CCL2 levels were measured using ELISA. We found higher serum level of MCP-1/CCL2 in children with BA (191.09±64.96 pg/ml) and CF (258.51±76.45 pg/ml) compared to healthy children (70.30±64.30 pg/ml, p=0.022, and p=0.068, respectively). Younger patients with BA had higher levels of MCP-1/CCL2, as well as children with CF, with levels decreasing gradually with age. We observed also higher levels of MCP-1/CCL2 in children with moderate to severe BA compared to mild BA. We documented the significantly higher level of MCP-1/CCL2 in children with these chronic pulmonary diseases than in healthy controls, which suggesting that investigation of serum MCP-1/CCL2 levels could turn out to be beneficial for the severity of the disease.