In order to demonstrate that there is a direct link between compliance with accounting principles and auditor’s opinion, which, of course, is „iltered” through professional judgement, the study starts from information provided by a representative medium-sized audit company located in the western part of Romania. The research starting point is represented by audit opinions expressed on statutory audit engagements for financial years ended 31 December 2008 and 31 December 2009, respectively. The study pursued the typology of audit opinions expressed for clients in portfolio during the two consecutive years and aimed to find explanations for the auditor issuing other opinions than qualified opinions on one hand, and on the other hand it aimed to establish the effects of non-compliance with accounting principles on the annual financial statements and, implicitly, on the audit opinion. Generally speaking, non-compliance with accounting principles in the preparation of the annual financial statements represents one of the elements that generate the change of the audit opinion, and the main causes for this type of behaviour from the side of audited companies are resulting from the influence of fiscal decisions, window dressing and “inadaptability” to the conditions of the economic and financial crisis. The relevance of the conclusions is based not only on the prerequisites and character of treated information, but also on their practical confirmation, by means of checking them with the involved business environment (investors, shareholders, administrators, business executives).