Background: The prevalence of speech-language impairments in children have been estimated for several languages, primarily in developed countries. However, prevalence data is lacking for developing countries, such as Nepal. Aims: (1) To obtain teacher estimates of incidence and overall prevalence of speech-language impairments and its subtypes as a function of gender, age and grade level; and (2) to validate the screening instrument on Nepalese children. Methodology: The adapted teachers' screening instrument, namely adapted Teachers' Speech and Language Referral Checklist (a-TSLRC), was administered in 2776 (690 and 2086) primary school children aged 5;00-11;11 years (mean = 8;11 years). The screening was conducted at four different points in time, i.e. Incidences I and II, and each incidence consisted of a testing and a retesting phase. Prior to this, teachers were trained in forum meetings, and an information sheet containing an overview of speech-language impairments, and guidelines/criteria for marking the occurrence of speech-language impairments in the TSLRC were disseminated. Outcomes & Results" Overall prevalence of speech-language impairments in children was estimated as 8.11%. Specifically, overall speech problems were estimated as 4.68%, and language problems as 8.0%. Additionally, the prevalence by subtypes of speech-language impairments as categorized in the TSLRC were reported to be 2.95% for an articulation/phonological problems, 2.09% for stuttering, 3.42% for a voice problems, 4.97% for a receptive language problems and 7.74% for an expressive language problems. The internal consistency among items was sufficient and a good intra-rater reliability was obtained. Conclusions & Implications: The study indicates that the overall results of speech-language impairments in children via the adapted in-Nepalese criterion-referenced instrument are supported by international studies. In addition, justifiable reliability and validity was obtained. Therefore, based on these overall evidence, this instrument can be useful for the screening of speech-language impairments in primary school children in Nepal.