The research objectives were aimed to scrutinize problems of quality control in accounting firms for accounting services in Nonthaburi. The samples used in this study were 105 accounting firms registered with the Department of Business Development with the business purpose was to provide accounting services in Nonthaburi province. The statistics used in data analysis were frequency distribution percentage mean standard deviation t-test and one-way ANOVA; then Least Significant Differentiation (LSD) was applied to test each pair. The results revealed that most chief accountants were 41-50 years old female with bachelors’ degrees and had more than eight years’ work experience. Most accounting firms were limited companies with the work duration period of serving 6 to 10 years with 1 to 5 employees and at least 50 customers. They had not been certified according to the announcement of the Department of Business Development. The overall problems regarding the quality control were relatively high. The highest aspect was related to ethics followed by the management responsibility within the accounting firms and work operation. Based on the hypothesis testing different ages and types of accounting had different opinions on quality control issues at 0.05 statistically significant difference; and different genders education levels experiences and work tenures number of employees number of customers and accreditation of accounting firms did not differ in terms of available opinions. ง Concerning problems regarding quality control in accounting firms employees should be promoted to enhance their knowledge and performance understand the quality assurance system of accounting firms. Also The Department of Business Development should provide trainings for accountants working for the accounting firms in order to achieve effective implementation and obtain higher potential for extra accounting quality.