Aims: Cardiogenic shock (CS) is an ominous complication of ST-elevation myocardial infarction (STEMI), despite the recent widespread use of reperfusion and invasive management. The Ruti-STEMI-Shock registry analysed the prevalence of and 30-day and 1-year mortality rates in ST-elevation myocardial infarction (STEMI) complicated by CS (STEMI-CS) over the last three decades. Methods and Results: From February 1989 to December 2018, 493 STEMI-CS patients were consecutively admitted in a well-defined geographical area of ~850,000 inhabitants. Patients were classified into six five-year periods based on their year of admission. STEMI-CS mortality trends were analysed at 30 days and 1 year across the six strata. Cox regression analyses were performed for comparisons. Mean age was 67.5 ± 11.7 years; 69.4% were men. STEMI-CS prevalence did not decline from period 1 to 6 (7.1 vs. 6.2%, p = 0.218). Reperfusion therapy increased from 22.5% in 1989-1993 to 85.4% in 2014-2018. Thirty-day all-cause mortality declined from period 1 to 6 (65% vs. 50.5%, p < 0.001), with a 9% reduction after multivariable adjustment (HR: 0.91; 95% CI: 0.84-0.99; p = 0.024). One-year all-cause mortality declined from period 1 to 6 (67.5% vs. 57.3%, p = 0.001), with an 8% reduction after multivariable adjustment (HR: 0.92; 95% CI: 0.85-0.99; p = 0.030). Short- and long-term mortality trends in patients aged ≥ 75 years remained ~75%. Conclusions: Short- and long-term STEMI-CS-related mortality declined over the last 30 years, to ~50% of all patients. We have failed to achieve any mortality benefit in STEMI-CS patients over 75 years of age.