In this paper, nineteen different immune peptides (cecropin, degensin and gambicin) of mosquito retrieved from National Centre for Biotechnology Information (NCBI) database were analysed and characterized using In silico tools. Primary structure analysis shows that most of the immune peptides are hydrophobic in nature due to the high content of non-polar residues. The presence of Cysteines residues was found only on defensin immune peptides of Anopheles gambiae, Culex quinquefasciatus, Aedes aegypti, Aedes albopictus, Culex pipiens and Anopheles stephensi infer that these proteinsmay formdisulphide (SS) bonds, which are regarded as a positive factor for stability. The aliphatic index computed by Ex-PasyÂs ProtParam infers that immune peptides may be stable for a wide range of temperature. Secondary structure analysis shows that most of the immune peptidesmixed secondary structure. The presence of disulphide (SS) bonds in the Q7PY14.4, ABB00933, EDS293341, AAC36346, AAO38519 and ABM92299 were predicted by CYS_REC tool and also identified fromthe three-dimensional structure using Rasmol tool. The disulphide bonds identified fromthe three-dimensional structure using the Rasmol toolmight be correct as the evaluation parameters are within the acceptable limits for the modeled 3D structures.