In the Republic of Congo, malaria remains one of the main causes of consultation in health centers, with children under 15 years old and pregnant women being the most vulnerable groups [
1,
2]. Like in almost all sub-Saharan African countries, the high level of resistance of
Plasmodium falciparum to chloroquine as well as the inefficacy of sulphadoxine-pyrimethamine and amodiaquine either singly or in combination for the treatment of uncomplicated malaria have led the Republic of Congo to change its anti-malarial drug policy for treating uncomplicated malaria to artemisinin-combination therapies (ACTs) in 2006 [
3]. Previous studies have shown that ACTs remain highly efficacious in Sub-Saharan Africa, including the Republic of Congo [
4‐
7]. However, the emergence of resistance to artemisinin derivatives, including ACTs in Southeast Asia is a serious public health concern. If resistance to ACTs may spread, particularly in sub-Saharan Africa, the public health implications could be disastrous, because no alternative drug is currently available with the same level of efficacy and tolerance than ACTs. In order to limit the development of
Plasmodium falciparum resistance to current antimalarial, the World Health Organization (WHO) has recommended a vigilant surveillance of resistant parasites [
8]. Recently, five principal mutations, namely the M476I, Y493H, I543T, R539T and C580Y in the
Plasmodium falciparum Kelch propeller domain (K13-propeller) have been found to be associated with delayed parasite clearance after ACTs therapy in Cambodia [
9]. Although no mutations associated with prolonged artemisinin clearance in Southeast Asia are found in sub-Saharan African regions, while diverse others mutations are identified even in isolates collected before or after the introduction of ACTs, regular surveillance is needed, taking into consideration the critical importance of ACTs in the control and elimination of malaria in these regions [
10‐
14]. Thus, the current study aimed at measuring the prevalence of
Plasmodium falciparum K13-propeller polymorphisms in clinical isolates collected from Brazzaville 10 years after the introduction of ACTs.