To achieve the full therapeutic potential offered by antimicrobial peptides, a greater knowledge of mechanisms underlying their interactions with microbial membrane is essential. In the present study, a dataset of known a-helical antimicrobial peptides (α-AMPs) is established and statistical investigation conducted into putative relationships between levels of microbial specificity and antimicrobial action and: relative amino acid frequency, net charge ratio, molecular weight, sequence length and pI. These analyses suggested that the residues D, G, H, K, L, M, V, W and Y play roles in both the levels of antimicrobial action and microbial specificity of the α-AMPs studied, whereas R appeared to play no such role(s). The molecular weights of α-AMPs ranged from 1155 to 7432 Da whilst sequence lengths varied between 10 and 48 residues although these properties of a-AMPs appeared to be generally unrelated to the microbial specificity and levels of antimicrobial action of these peptides. The pI of a-AMPs s ranged between 8.9 and 12.7 whilst the total net charge ratio and the overall net charge of these peptides ranged from 1.47 to 5.86 and –5 to +16 respectively. Statistical analysis showed that each of these properties plays a role in the microbial specificity and levels of antimicrobial action shown by these peptides. It is concluded that varying the interplay of physiochemical properties is a strategy adopted by α-AMPs to enhance the versatility of their antimicrobial action, thereby making the acquisition of resistance to this action by microbes more difficult.