Abstract: A portable pet care system comprises a first end or base portion having a bottom and four side walls, a second end or top portion having a cover and four side walls, and a collapsible extension portion for placement between the two end portions and having four side walls, one of which has a pet-accessible opening. When the portable pet care system is in a travel configuration, the collapsible portion is adapted to fold up and fit entirely within the first and second end portions, which are sized to fit one within the other to define a travel box. The travel box contains liners, pet litter, a scoop, and a handle. When the portable pet care system is in an in-use configuration, the end and collapsible extension portions assemble into a disposable litter box or pet carrying container.