Some salaried employees are entitled to overtime pay. The salaried employees entitled to overtime pay are referred to as nonexempt employees. The salaried employees that are not entitled to overtime pay are referred to as exempt employees.
In the U.S. the employer and employees are required to comply with the federal Fair Labor Standards Act and with their state's rules for overtime pay. (The rules which are more advantageous for the employees must be followed.)
In short, an employer cannot avoid paying overtime or an overtime premium merely by classifying an employee as salaried.
One of the criteria for determining whether a salaried employee is exempt is the employee's salary. Unless exempted due to other criteria, an employee with a gross salary of less than $23,600 per year ($455 per week) is nonexempt and must be paid for his or her overtime hours.
For additional criteria for exempt or nonexempt salaried employees contact your state and also the U.S. Department of Labor's Wage and Hour Division.