In a small saucepan place the sugar, water, and lime juice.

Simmer over low heat until sugar dissolves, remove from heat.

Allow lime syrup to cool completely.

Run a lime wedge around glass.

Spread sugar on glass, dip glass to rim.

To a cocktail filled with ice add vodka, watermelon juice and lime syrup.

Shake until well chilled, strain into rimmed glass, Garnish with lime slice.