Maize has been intercropped with different forage species, especially Brachiaria spp., for different purposes and at different times: after maize harvest, as a food source for cattle; and exclusively for the production of straw to maintain a no-tillage system, which is the main purpose of intercropping in western Paraná. The objective was to investigate the effects of different rates of nitrogen (N) and potassium (K) topdressing on grain yield and components of yield for maize intercropped with Brachiaria ruziziensis. The experiment was conducted in Paraná State, Brazil. The experiment used a completely randomized block factorial design (4 × 3) with four replications. Treatments for the first factor consisted of sowing maize intercropped with Brachiaria ruziziensis with four rates of N topdressing (0, 80, 100 and 120 kg ha−1) applied as urea. For the second factor were rates of K topdressing (0, 30 and 50 kg ha−1), applied in the form of potassium chloride. During at sowing fertilization was performed with of 30, 26 and 50 kg ha−1 of N, phosphorus and K, respectively. The following variables were evaluated: plant height, first ear height, stem diameter, number of tillers per plant, mass of 1,000 grains, grain yield. The results showed that application of N topdressing promoted increased grain yield of maize intercropped with Brachiaria ruziziensis until N rate of 85 kg ha−1. Isolated application of K did not influence the variables studied.