Hello, A long while back I posted about this leak but at the time I wasn't able to really narrow down the cause of the leak. However I believe I have now found the issue and that is whenever PJSIP receives an INVITE without an SDP the associated dialog(s) are never freed from memory. There is something increasing the reference counter by 1 but never decreasing it to allow the dialog(s) to be freed. The code to reproduce this is available from my older post here: http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/2018-February/040858.html If you run that example and send to that process an INVITE that does not contain an SDP, the dialog reference counter gets decreased to 4 when the call is terminated. Associated transactions get properly destroyed but the dialog does not. If you then run that same example and send an INVITE that *does* contain an SDP, the reference counter get decreased to 3 when the call is terminated and the dialog gets destroyed when the associated transactions get destroyed. This bug still exists in both PJSIP 2.8 and the master branch @ 8c76e17145c0856b8d925da41e1ba43062e8d2e5. - Brian