Prior research has suggested that fixed-time (FT) schedules of reinforcement do not necessarily preclude the acquisition of appropriate behavior (e.g., mands) when combined with differential reinforcement (DRA). These studies also note that dense FT schedules are more likely to interfere with DRA packages than lean FT schedules. In the current investigation, we examined whether similar findings would occur with FT schedules of negative reinforcement. Schedule analyses were conducted with two participants following functional analyses that identified escape from task demands as the maintaining variable for problem behavior. Differential negative reinforcement of alternative behavior (DNRA) was implemented first to establish behavioral control (decreased problem behavior and increased compliance). Breaks (negative reinforcement) were then concurrently delivered on a FT basis under either dense (at a greater rate than that obtained during DNRA alone) or lean (at a lower rate than that obtained during DNRA) reinforcement schedules. In general, results showed that FT escape did not preclude compliance when the FT schedule was lean, but treatment gains were significantly disrupted when dense FT schedules were superimposed.