Given the time and money invested in higher education by students, parents and governments, there is considerable interest in the economic outcomes of postsecondary graduates. Most assessments of recent graduates have focused on their short-term, early labour market results. As new entrants to the labour force, recent postsecondary graduates may be particularly vulnerable to the economic cycle. Consequently, comparisons of short-term outcomes across graduating cohorts may be highly dependent on prevailing economic conditions and may not reflect the longer-term returns on investments. This is the first study to compare the long-term labour market outcomes of two cohorts of young postsecondary graduates using linked census and tax data. Specifically, graduates who were 26 to 35 years old in 1991 were followed from 1991 to 2005 (when they were 40 to 49 years old) and compared with a similarly aged 2001 cohort, which was followed from 2001 to 2015.The results suggest that median cumulative earnings were higher among members of the more recent cohort of male and female postsecondary graduates. Increases were observed across all postsecondary levels and across most major disciplines where sample sizes were large enough to permit analysis. Also, no discipline registered a decline in cumulative earnings. Although the economic conditions faced by the 2001 cohort over the 15-year study period were generally more favourable, this cohort also registered higher earnings than the 1991 cohort during the latter portion of the period (i.e., when the 2001 cohort was faced with an economic recession). Furthermore, the initial labour market conditions upon graduation (an important determinant of career earnings) were similar for both cohorts. The improvements in long-term earnings for postsecondary graduates are important in light of the significant increase in the number of graduates over the period. However, the results also indicate that the number of years of union membership declined or remained steady across cohorts of male and female postsecondary graduates. Furthermore, while women with postsecondary qualifications registered increases in the number of years of employer-sponsored pension plan coverage, their male counterparts experienced mixed results depending on their level of postsecondary studies.