<p>Background: In the recent years, there has been an increasing interest in secretory production of recombinant proteins, due to its various advantages compared with intracellular expression. Signal peptides play a critical role in prosperous secretion of recombinant proteins. Accordingly, different signal peptides have been assessed for their ability to produce secretory proteins by trial-and-error experiments. The aim of this study was to evaluate the effect of L-asparaginase II signal peptide on the recombinant human Growth Hormone (hGH) protein secretion in the <em>Escherichia coli (E. coli)</em> host.<br /> Methods: Cloning and expression of a synthetic hGH gene, containing L-asparaginase II signal sequence was performed in <em>E. coli</em> BL21 (DE3) using 0.1 <em>mM</em> IPTG as an inducer at 23^o<em>C</em> overnight. Periplasmic protein extraction was performed using three methods, including osmotic shock, osmotic shock in the presence of glycine and combined Lysozyme/EDTA osmotic shock. Afterwards, the hGH expression was determined by SDS-PAGE.<br /> Results: Based on experimentally obtained results, hGH protein is expressed as inclusion body even in the presence of L-asparaginase II signal peptide.<br /> Conclusion: Therefore, this signal peptide is not effective for secretory production of the recombinant hGH.</p>