The sustainable logistics business case (SLBC) provides underlying argumentation to convince decision makers to approve initiatives within sustainable logistics. Little knowledge exists on how companies conduct SLBCs or the challenges that need to be addressed. The purpose of this paper is to explore how companies conduct SLBCs, to increase the understanding of how perceived challenges can be addressed. Potential challenges were identified in literature on business cases models in general and sustainable logistics business cases. As third-party logistics providers (3PL) are big contributors to emissions and often are responsible for designing logistics setups, they were focused in the empirical study. How SLBC were conducted was investigated based on interviews with managers responsible for conducting SLBCs and the responses triangulated with information derived from actual business cases. Despite the careful selection of 3PLs well ahead within the area, few challenges were perceived by the studied companies. This does not imply that challenges do not exist but can rather be described as a consequence of their pragmatic and inward-looking perspective. Examples of how to address challenges are provided. The compiled list of SLBC challenges provides an overview that was missing in literature.