Cotton is the most important fiber crop of world which supports the economy of several countries. Its seed oil is also an important source of edible oil used for cooking purpose. Cotton plant is damaged by a number of insect pests which not only reduce its yield but also impairs its quality as well. Insects evolve very rapidly with the passage of time and new races develop which is a very serious threat to cotton production and a big challenge for cotton breeders. To cope with this challenge it is inevitable to develop insect resistant varieties using modern breeding techniques. Marker assisted breeding serve as a very valuable tool for plant breeders which can be used to develop genotypes with desirable genetic architecture. The method requires scoring of phenotypic traits and genotyping with DNA markers. Data of DNA markers is used to map QTLs usually the techniques used for mapping QTLs in crop plants are, simple interval mapping, composite interval mapping, marker regression,simplified composite interval mapping. Bayesian methods, single-marker locus analysis, and multiple interval mapping.