The magnetohydrodynamic stability of diffuse, axisymmetric toroidal plasma configurations with large elongation in the direction of the axis of symmetry and large aspect ratio is investigated. In an asymptotic expansion the elongation and aspect ratio are related and both are made large. This expansion reduces the equilibrium relations in leading order to an ordinary differential equation readily susceptible to numerical solution or, in some cases, analytical solution. The same expansion procedure is also applied to the linearized stability analysis and both partial differential equations and a Rayleigh–Ritz quotient for the eigenvalues and eigenvector result. Belt pinch and doublet shapes for various current density profiles are examined for internal and external modes for both high and low &bgr; forms of the equilibrium. Growth rates and eigenfunctions for the discrete modes are given and general features of the spectrum are discussed.