The fact that loops assume important roles in molecular functions and biological recognition is well known. In this study the Propensity and the Relative entropy of amino-acids in loop structures connecting beta-strands are calculated. Results showed that Asn is the most frequently occurring amino-acid in loop regions connecting beta-strands, followed by Gly, Asp, Ser, and Thr. Results presented here can serve for modeling loop structures connecting beta-strands in proteins.