One hundred and ninety-three hemato-oncologists and nuclear medicine specialists from 23 countries joined the 2-day Third International Workshop on Interim Positon Emission Tomography in Lymphoma held in September 2011. Forty scientific posters were presented or discussed in the plenary session. Final results of international validation studies of Deauville criteria and change in maximum standardized uptake value (ΔSUV(MAX)) analysis in Hodgkin lymphoma (HL) as well as non-Hodgkin lymphoma (NHL) were reported. These studies were confirmatory of the prognostic value of interim positron emission tomography (PET) in 261 patients with advanced HL after two cycles of ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) when reported with the 5-point scale and in 120 patients with diffuse large B-cell lymphoma (DLBCL) after two cycles of a rituximab-containing immunochemotherapy regimen when using ΔSUV analysis. A preliminary consensus on interim PET was established among experts on the assessment of marrow response, refinement of scores 4 and 5 of the 5-point scale, the need to focus on interim PET results for NHL other than DLBCL, methods to compute ΔSUV and factors affecting ΔSUV measurements. Recommendations were given on how to use ΔSUV analysis in NHL taking into account the levels of initial SUV(MAX) and interim SUV(MAX). For the next meeting (October 2012), the majority of the audience strongly favored extending the topics, including in the workshop all aspects of PET in lymphoma, rather than just limiting it to interim PET.