Objective One of the treatments that have been proposed recently for deaf children is cochlear implant. It is a new technology and an accepted treatment for children with hearing impairment. In recent years, researchers have paid special attention to the family and its relationship with the developmental skills of children with hearing loss. Clinical experience has also shown that emotional performance and psychological problems of the caregiver can have unfavorable effects on cochlear implanted children’s developmental skills. Therefore, the present study was conducted with the aim of determining the relationship of parent-child stress with developmental skills of children with cochlear implants. Materials & Methods The present study was a correlational study that was conducted in 2015. The study population comprised all children undergone cochlear implant surgery in Al-Zahra Hospital of Isfahan. Out of them, 57 participants (34 boys and 23 girls) were selected randomly. To evaluate the research variables, the Parenting Stress Index, Leiter International Performance Scale, the Vineland Social Maturity Scale, the Language Development Scale, and the Cochlear Implanted Children’s Communication Performance Scale were used. The data of the research were analyzed using descriptive statistics as well as correlational and regression analysis methods. SPSS version 22 was used for data analysis. Results The results of analyzing data indicated that there is a negative (reverse) significant correlation between parent-child stress and language development (-0.59), social development (-0.38), and communication development (-0.54) of children (P≥0.01). According to regression analysis investigating the explanation of language development (criterion variable) based on parent-child stress (predictive variables), the coefficient of determination equals to 0.34 (R2=0.34) and thus, 34% of the variance in the dependent variable (language development) are explained via parent-child stress. Also, in explaining the social development (criterion variable) based on parent-child stress (predictive variables), the coefficient of determination equals to 0.14 (R2=0.14) and thus, 14% of the variance in the dependent variable (social development) are explained via parent-child stress. Also, in explaining communication function (criterion variable) based on parent-child stress (predictive variables), the coefficient of determination equals to 0.29 (R2=0.29) and thus, 29% of the variance in the dependent variable (communication function) are explained via parent-child stress.   Conclusion The results of this study showed that parent-child stress had a significant effect on developmental skills of children with cochlear implants. Due to the importance of developmental skills in children with cochlear implants, the results of this study warned the need to provide counseling and psychological support for this group of parents. Accordingly, the programs should be offered in the form of workshops for mothers of these children. Also, psychologists and family counselors and experts in family therapy are recommended to have special attention to the role of stress in parent-child relationships in treatment programs and training.