Previous studies have not shown a survival advantage for smoking reduction. The authors assessed survival and life expectancy according to changes in smoking intensity in a cohort of Israeli working men. Baseline smokers recruited in 1963 were reassessed in 1965 (n = 4,633; mean age, 51 years) and followed up prospectively for mortality through 2005. Smoking intensity at both time points was self-reported and categorized as none, 1-10, 11-20, and ≥21 cigarettes per day. Change between smoking categories was noted, and participants were classified as increased (8%), maintained (65%), reduced (17%), or quit (10%) smoking. During a median follow-up of 26 (quartiles 1-3: 16-35) years, 87% of participants died. Changes in intensity were associated with survival. In multivariable-adjusted models, the hazard ratios for mortality were 1.14 (95% confidence interval (CI): 0.99, 1.32) among increasers, 0.85 (95% CI: 0.77, 0.95) among reducers, and 0.78 (95% CI: 0.69, 0.89) among quitters, compared with maintainers. Inversely, the adjusted odds ratios of surviving to age 80 years were 0.77 (95% CI: 0.60, 0.98), 1.22 (95% CI: 1.01, 1.47), and 1.33 (95% CI: 1.07, 1.66), respectively. The survival benefit associated with smoking reduction was mostly evident among heavy smokers and for cardiovascular disease mortality. These results suggest that decreasing smoking intensity should be considered as a risk-reduction strategy for heavy smokers who cannot quit abruptly.