Network scale up (NSU) is a novel approach to estimate parameters in hard to reach populations throughasking people the number of individuals they know in their active social network. Although the method havebeen used in hidden populations, advantages of NSU indicate that exploration of applicability to disease likecancer might be feasible. The aim of this study was to assess the application of NSU to estimate the size of thepopulation of breast, ovarian/cervical, prostate, and bladder cancers in the South-east of Iran. A total of 3,052(99% response rate) Kermanian people were interviewed in 2012-2013. Based on NSU, participants were askedabout if they know any people on their social network who suffered from breast, ovarian/cervical, prostate, andbladder cancers, if yes, they should enumerate them. A total of 1,650 persons living with four types of cancers(breast, ovary/cervix, prostate, and bladder) were identified by the respondents. Totally, the prevalence of peopleliving with the four types of cancers was 228.4 per 100,000 Kermanian inhabitants. The most prevalent cancerwas breast cancer, at 168.9 per 100,000, followed by prostate cancer with 116.9, ovarian/cervical cancer with99.8, and bladder cancer with 36.3 per 100000 Kerman city population. NSU values provide a usable but notvery precise way of estimating the size of subpopulations in the context of the four major cancers (breast, ovary/cervix, prostate, and bladder).