This paper offers adiabatic solutions for a finite-width, hydrodynamic journal bearing with rough surfaces. An average flow model is adopted to describe the roughness effects. Longitudinal, isotropic and transverse roughnesses are discussed. The film viscosity is taken to be an exponential function of temperature. The performance characteristics are obtained for different independent parameters including eccentricity ratio in the range 0.2–0.7, diameter-to-length ratio, D/ L, in the range 0.1–10, clearance to combined root mean square value of roughness ratio in the range 2–10, and journal speed, N, from 100 to 10 000 rev/min. Numerical results indicate that thermal effects are more pronounced in a long bearing, at higher eccentricities and rotational speeds. For a long bearing, the values for maximum temperature and load capacity are smallest for longitudinal roughness, while they are largest for transverse roughness. However, for a short bearing the reverse trend is true. In addition, it is found that the effect of roughness direction on the maximum temperature is not significant compared with its effect on the load capacity.