-Several factors can influence wheat crop yield, they include the interference imposed by weeds is one of the most important. The objective of this study was to evaluate the critical periods of weed interference in early wheat in the midwest of the state of Paraná, Brazil. The experiment was conducted in an experimental area located in Campo Mourão -PR, during the year 2013, using the BRS Pardela cultivar. The treatments consisted of periods of coexistence and weed control in wheat. Periods of coexistence and control were 0, 7, 14, 28, 35 and the whole cycle at days after crop emergence (DAE). Number of reproductive tillers per plant, spike length, number of spikelets per spike, plant height and wheat crop yield, were significantly affected by coexistence with prevailing infestation of Raphanus raphanistrum, therefore, a critical period of interference was determined at 16 to 24 DAE. de 0, 7, 14, 28, 35 Keywords: competition, Raphanus raphanistrum, Triticum aestivum. RESUMO -Vários fatores podem influenciar a produtividade da cultura do trigo, dos quais a interferência imposta pelas plantas daninhas é um dos mais importantes. O objetivo deste trabalho foi avaliar os períodos críticos de interferência das plantas daninhas em trigo precoce na região Centro Ocidental Paranaense. O experimento foi desenvolvido em área experimental localizada em Campo Mourão-PR, durante o ano de 2013, utilizando o cultivar BRS Pardela. Os tratamentos foram constituídos de períodos de convivência e controle das plantas daninhas na cultura do trigo. Os períodos de convivência e controle foram