Although many proposals exist in market addressing the Routing in HWSN issue, but node heterogeneity of SNs has not been exploited to its full potential. So there is a requirement of categorization of SNs based upon different performance evaluation metrics. Motivated by the above facts, in this book, we provide a complete categorization of various heterogeneous routing protocols for WSNs. The main objectives of the chapter are summarized as follows: i) to provide the detailed discussion on different protocols as per the defined taxonomy ii) to emphasize the merits and demerits of existing protocols in the literature with respect to various performance evaluation parameters. iii) A complete taxonomy is provided for heterogeneous WSNs. iv)Protocols in different categories are analysed with respect to different performance evaluation parameters. v)Finally, a complete comparison of various protocols with respect to different metrics with advantages/disadvantages is provided in the text.