A modular case and method of forming the same, the case preferably formed from a plurality of panels, edge members and corner pieces having ribs. The panels, edge members and corner pieces are preferably connected to align the ribs, forming substantially continuous ribs capable of distributing forces over a large area of the modular case. The case is most preferably made of plastic, the connections preferably being hot-plate welds. Most preferably, the panels and edge members have a dual skin construction with internal ribs, proving for greater strength and allowing for superior structural properties including air-/water-tight integrity. Edge members are preferably formed with protuberances to allow for better base-to-lid and case-to-case engagement. Hardware attachments to the modular case can be advantageously made while distributing the force on attachment points and without compromising structural integrity.