The 4th International Conference on Acoustics and Vibration (ISAV2014) follows previous conferences which were successfully held in Tehran. The previous conferences were both well received by experts in acoustics and vibration and showed that there is a great interest in Iran for this important and vital field of science. The 4th International Conference on Acoustics and Vibration (ISAV2014) is jointly held by Iranian Society of Acoustics and Vibration (ISAV) and Iran University of Science & Technology from 10 Dec. 2014 in Tehran. ISAV2014 will provide an international forum for presentation and exchange of the latest scientific achievements and technological developments in the fields of acoustics and vibration. The program will feature plenary and keynote presentations, contributed oral and poster papers, a specialized commercial exhibition, and a number of technical workshops. A student competition for selection of the best BSc, MSc and PhD theses in acoustics and vibration is another exciting part of ISAV2014. On behalf of the organizing committee, it is a great pleasure for me to invite you to participate in this special event. We look forward to seeing you in Tehran at ISAV2014.