Defending champion Novak Djokovic was handed a tough opening round at Wimbledon when Friday's draw paired him with Germany's Philipp Kohlschreiber.
The Serb, who beat Roger Federer in last year's final to win the title for a second time, could then face former champion Lleyton Hewitt in the second round.
Kohlschreiber had match points against Federer at Halle last week and at number 33 in the world he only just missed being seeded for the grasscourt grand slam.
Federer will play Bosnia's Damir Dzumhur.
British hope and third seed Andy Murray, who is in Federer's half of the draw, begins against Mikhail Kukushkin of Kazakhstan.
Frenchman Jo-Wilfried Tsonga could be waiting in the last 16 with Nadal or fellow Spaniard David Ferrer in the quarters.
Twice former champion Rafa Nadal, seeded 10th and also in the bottom half of the draw, will play Brazil's Thomaz Bellucci.
Wawrinka, seeded four and on course for a semi-final against Djokovic, plays Joao Sousa.
Czech Petra Kvitova, who stormed to her second title last year when she crushed Canada's Eugenie Bouchard in the final, will begin against Kiki Bertens of the Netherlands.
The top half of the women's draw looks stronger than the bottom with world number one Serena Williams joined by Ana Ivanovic, Maria Sharapova and five-times winner Venus Williams.
American sisters Serena and Venus could meet in the last 16.
Serena should have little trouble in the first round after being drawn against Russian qualifier Margarita Gasparyan.