The purpose of this study was to investigate the impact of compatibility and connectivity of Information Technology Infrastructure (ITI) on reliability and access of customer service delivery in the Nigeria commercial banks. The study selected 8 commercial banks out of the 20 commercial banks in Nigeria as to generalize her findings. The study conveniently selected 40 customers’ from the eight banks, thereafter a total of 40 copies of the questionnaire that is 5copies per banks was randomly distributed to the 40 customers of the banks and the 40 questionnaire were fully attended to and retrieved. Simple percentages, tables were used to analyze the respondent demographics, while the Spearman’s rank order correlation coefficient was used to analyze the four hypotheses; this was made easy with the use of statistical package for social sciences SPSS. The findings therefore revealed that compatibility and connectivity of ITI has strong and positive impact on reliability and access of customer service delivery. Therefore, the study has bridged knowledge by revealing that the two component of ITI used in this study impact on the two components of customer service delivery as used in this work. We, recommended that commercial banks should improve on their ITI compatibility and connectivity by training and retraining their IT personnel to be responsive to customer’s complaints, also should overhaul their ITI facilities regularity in other words by improving their facilities, so as to deliver quality service and access to service.