The 1997–98 season ended with Gilchrist top of the dismissals chart for the fourth season in a row with an improved batting average of 47.66, despite playing in only six of the ten qualifying Shield matches due to his becoming a regular member of the national limited overs team. Gilchrist registered his maiden–first-class double century with an unbeaten 203 against South Australia early in the season, before returning late in the season after his international commitments were over. He added 109 against Victoria, and played in the Sheffield Shield final victory over Tasmania, although he scored only eight. There was disappointment for the team in the Mercantile Mutual Cup, losing the semi-final to Queensland. The following season saw Gilchrist's domestic appearances diminish due to his international commitments: he made only a single appearance in the Mercantile Mutual Cup, but still managed to help Western Australia defend the Sheffield Shield, scoring a century in the qualifying rounds.