In recent years, structures made up of functionally graded materials (FGMs) have received considerable attention for use in high-temperature applications. In this article, a finite element formulation based on First-Order Shear Deformation Theory (FSDT) is used to study the thermal buckling and vibration behavior of truncated FGM conical shells in a high-temperature environment. A Fourier series expansion for the displacement variable in the circumferential direction is used to model the FGM conical shell. The material properties of the truncated FGM conical shells are functionally graded in the thickness direction according to a volume fraction power law distribution. Temperature-dependent material properties are considered to carry out a linear thermal buckling and free vibration analysis. The conical shell is assumed to be clamped-clamped and has a high temperature specified on the inner surface while the outer surface is at ambient temperature. The one-dimensional heat conduction equation is used across the thickness of the conical shell to determine the temperature distribution and thereby the material properties. In addition, the influence of initial stresses on the frequency behavior of FGM shells has also been investigated. Numerical studies involving the understanding of the role of power law index, r/h ratios, and semi-vertex angle on the thermal buckling temperature as well as on vibration have been carried out. © 2005 Elsevier Ltd. All rights reserved.