Background: To address the risks of adverse pregnancy outcomes and future type 2 diabetes associated with gestational diabetes mellitus (GDM), its early detection and timely treatment is essential. In the absence of an international consensus, multiple different guidelines on screening and diagnosis of GDM have existed for a long time. This may be changing with the publication of the recommendations by the International Association of Diabetes and Pregnancy Study Groups. However, none of these guidelines take into account evidence from or ground realities of resource-poor settings. Objective: This study aimed to investigate whether GDM projects supported by the World Diabetes Foundation in developing countries utilize any of the internationally recommended guidelines for screening and diagnosis of GDM, explore experiences on applicability and usefulness of the guidelines and barriers if any, in implementing the guidelines. These projects have reached out to thousands of pregnant women through capacity building and improvement of access to GDM screening and diagnosis in the developing world and therefore provide a rich field experience on the applicability of the guidelines in resource-poor settings. Design: A mixed methods approach using questionnaires and interviews was utilised to review 11 GDM projects. Two projects were conducted by the same partner; interviews were conducted in person or via phone by the first author with nine project partners and one responded via email. The interviews were analysed using content analysis. Results: The projects use seven different screening procedures and diagnostic criteria and many do not completely adhere to one guideline alone. Various challenges in adhering to the recommendations emerged in the interviews, including problems with screening women during the recommended time period, applicability of some of the listed risk factors used for (pre-)screening, difficulties with reaching women for testing in the fasting state, time consuming nature of the tests, intolerance to high glucose load due to nausea, needfor repeat tests, issues with scarcity of test consumables and lack of equipment making some procedures impossible to follow. Conclusion: Though an international consensus on screening and diagnosis for GDM is welcome, it should ensure that the recommendations take into account feasibility and applicability in low resource settings to ensure wider usage. We need to move away from purely academic discussions focusing on sensitivity and specificity to also include what can actually be done at the basic care level.[