This research aimed primarily to explore the demographic and marketing factorsaffecting customer satisfaction with CAT 009 International Call Service provided byCAT Telecom Public Company, Limited. Close-ended questionnaires were utilized forcollecting data from 400 customers in Bangkok. The data analysis used IndependentSample T-test, One-way ANOVA, and multiple regressions. The results indicated thatthe majority of respondents were females between 25-34 years of age. Most of themhad a Bachelor’s Degree, worked for private companies, and earned a monthly salarybetween 10,000-20,000 baht. Additionally, the results revealed that the differencesin gender, age, occupation, educational background, and income had no significantinfluence on the customer satisfaction with CAT 009 International Call Service. Theresults also showed that the marketing mix factors of product, place, distributionchannels, promotion, and process effected customer satisfaction with CAT 009International Call Service at the statistically significant level of 0.05. However, themarketing factors of price, people, and physical evidence had no significant influenceon the customer’s satisfaction toward CAT 009 International Call Service.