Dual-chamber pneumatic vibration isolators have a wide range of applications for vibration isolation of vibration-sensitive equipment. Recent advances in precision machine tools and instruments such as medical devices and those related to nano-technology require better isolation performance, which call be efficiently achieved by precise modeling- and design- of the isolation system. This paper discusses all efficient transmissibility design method of a pneumatic vibration isolator wherein a complex stiffness model of a dual-chamber pneumatic spring developed ill Our previous Study is employed. Three design parameters, the volume ratio between the two pneumatic chambers, the geometry of the capillary tube connecting the two pneumatic chambers, and, finally, the stiffness of the diaphragm employed for prevention of air leakage, were found to be important factors in transmissibility design. Based oil a design technique that maximizes damping of the dual-chamber pneumatic spring, trade-offs among the resonance frequency of transmissibility, peak transmissibility, and transmissibility in high frequency range were found, which were not ever stated ill previous researches. Furthermore, this paper discusses the negative role of the diaphragm in transmissibility design. The design method proposed in this paper is illustrated through experimental measurements. (C) 2009 Elsevier Ltd. All rights reserved.