This study investigated the effect of manual method of instruction on grammatical skills of pupils with profound pre-lingual hearing impairment in Ibadan, Oyo State. Two hypotheses were formulated for the study while the pretest-posttest, control group quasi-experimental research design was adopted for the study. The treatment (manual method) was cross-examined with gender and socio-economic status of pupils with profound pre-lingual hearing impairment (PPHI) for a period of 8 weeks. The Test of Written Language in English (α =0.88) and Socio-economic Status Scale was used for data collection. Data generated were analysed with t-test and Analysis of Covariance (ANCOVA) at p<0.05. Results revealed no significant effects of parents’ socio-economic status on English grammatical skills of PPHI. Also, no significant effect of treatment and gender (F = 2.870, p > 0.05, eta square = 0.74) was observed on (1,16) English grammatical skills of the participants. The study concluded that neither
gender nor parental socio-economic status has significant effect on English grammatical skills construction of the pupils with profound hearing impairment. Hence, this study recommends that irrespective of family socio-economic status, children with profound prelingual hearing impairment should be exposed to early language environment through manual communication.