**1. Introduction**

The monitoring and identification of drug-resistant *P. falciparum* strains is paramount to the fight against malaria. The traditional identification of resistant parasite strains is by *in vivo* and/or *in vivo* drug susceptibility assays. Although these methods are effective in identifying resistant strains, they are faced with an array of challenges. The most profound challenge being faced by both *in vivo* and *in vitro* techniques is the cost and time associated with them. Since malaria is mostly endemic in poor countries, it is imperative to identify cost-friendly methods for the surveillance and identification of resistant parasites.

One method that shows a lot of promise in the identification of resistant parasite strains is the use of polymerase chain reaction and sequencing techniques to identify the molecular markers of resistance that are associated with resistance to a particular antimalarial drug (s). The ever-improving knowledge in malaria parasite genomics has made it possible to identify mutations that are associated with resistance to antimalarial drugs. Identification of these markers in resistant strains and the validation of these markers using genome editing techniques such as Crispr-Cas9 have been possible, making us confident that, a parasite will be resistant to an antimalarial drug when the molecular marker of resistance-associated to it is identified in the parasite, without the performance of *in vitro* drug susceptibility assay. The use of molecular markers of resistance in identifying parasite-resistant strains has not just made it possible to identify resistant parasite strains, but also to predict how fast a resistant strain is emerging and how fast it is spreading. From the aforementioned advantages, it is clear that the most cost-friendly, time-saving, high through-put, and robust technique to use in identifying the emergence and spread of a resistance parasite strain by PCR and sequencing techniques to identify molecular markers of resistance to antimalarial drugs.

This chapter will focus on the *Plasmodium* parasite molecular markers of resistance responsible for antimalarial drug resistance. The mechanism of resistance due to mutations or increase in copy number in the molecular markers of resistance to the different antimalarial drugs will be elaborated. The epidemiology of different molecular markers will be also addressed.
