Distress has been recognized as the “6^th Vital Sign” in cancer care, and guidelines recommend routine screening in all patients. Despite this, screening for distress is rarely conducted or evaluated. A program of online screening for distress was implemented at our centre for all new lung cancer patients during their first visit to the clinic. Patients were randomly assigned to one of three conditions: 1) minimal screening(the Distress Thermometer (DT) plus usual care); 2) full screening (DT, Canadian Problem Checklist (CPC), Pain Thermometer (PT), Fatigue Thermometer (FT), PSSCAN Part C and personalized report summarizing concerns); or 3) triage (full screening plus option of personalized phone triage). Patients were reassessed 3 months later. 549 lung cancer patients were assessed at baseline (89% of all patients), and 75.5% of these retained for follow-up. Almost 63% of lung cancer patients scored over the DT cutoff for high distress (≥4) at baseline and 44% had high distress at 3-months. Twenty percent fewer patients in triage continued to report high distress at follow-up compared to the other two groups, and triage patients also reported fewer problems with coping, pain and problems with family conflict compared to minimal screening. The best predictors of anxiety and depression at follow-up were baseline levels and receiving a referral to psychosocial services. From this and other seminal work in screening for distress, we conclude that routine online screening is feasible and may help to reduce future distress levels, pain and other commonly experienced problems in lung cancer patients. However, screening alone is not sufficient, as follow-up referral to appropriate resources was also necessary in order to improve outcomes over time. Screening programs should include both broad-based measures of distress and screening questions for specific practical and psychosocial problems, followed by referral to appropriate resources using standardized algorithms.