As strategies targeting undernutrition and infections become increasingly successful in low- and middle-income countries (LMICs), a second challenge has appeared, namely premature onset of non-communicable diseases (NCDs). In LMICs, NCDs are often related to exposure to undernutrition and infections. As NCDs strike societies and individuals with impaired resistance or a deficient health (care) state, why not label such diseases 'opportunistic', in analogy with opportunistic infections attacking individuals with HIV? We propose the concept of opportunistic NCDs, hoping that fighting against infections, and for better maternal and child health, is becoming acknowledged as essential for the early prevention of NCDs.