We present Monte Carlo results for the equation of state of a fluid in which the intermolecular potential consists of a hard core of diameter a and an attractive tail which is of the form of a Yukawa function, - exp (—λ(r-σ))/r with λ= 1.8/σ. These results are compared with those obtained from perturbation theory, the mean spherical approximation (MSA), and three related approximation schemes. While perturbation theory works rather well for this system, the MSA is considerably less satisfactory. However, the exponential and linearized exponential modifications of the MSA and the generalized MSA all give good results for this system. © 1978 Taylor & Francis Group, LLC.