Respiratory diseases are the leading cause of hospitalizations in Brazil (excluding hospital admissions related to childbirth, pregnancy, and postpartum). To analyze the trend and seasonality of hospitalizations for respiratory diseases in Salvador, Bahia State, Brazil, 1998-2009, a time trend study was performed using simple linear regression. Hospitalization rates for all respiratory diseases and specifically for asthma, chronic obstructive pulmonary disease (COPD), and pneumonia were calculated by year and age group. Hospitalizations for all respiratory diseases decreased by 45.6% (β = -2.2; p < 0.001); those due to asthma showed the largest decline (annual average 1.2/10,000), pneumonia showed the largest reduction until 2002, subsequently tending to stabilize, and COPD remained unchanged. The under-5-year age group showed the largest decline in hospitalizations for all respiratory diseases. There was no seasonality in hospitalizations for COPD. There was a reduction in the burden of hospitalizations due to respiratory diseases in Salvador, mainly due to the drop in asthma and pneumonia in children < 5 years. However, the city still has hospitalization rates for respiratory diseases that are higher than in other large Brazilian cities.