Vejnarová competed in the 2002, 2006 and 2010 Winter Olympics for the Czech Republic. Her best performance was 13th, as part of the 2006 Czech relay team. Her best individual performance was 23rd, in the 2002 individual. In 2006, she finished 43rd in the sprint, 35th in the pursuit and 53rd in the individual. In 2010, she finished 60th in the sprint, 55th in the pursuit and the individual, as well as 16th in the relay.