A box for storing flies used for fishing including a cover assembly having two dish-like cover portions, each of which cover portions includes a central wall part, and side wall parts around the periphery of the central wall part projecting generally in the same direction away from the central wall part and having a continuous distal edge portion; and a hinge having hinge portions attached to the side wall parts adjacent second sides of the central wall parts. The hinge affords pivotal movement of the cover portions between a closed position with the distal edge portions of the cover portions opposed to, closely spaced from, and generally aligned with each other, and an open position with the distal edge portions spaced away from and out of alignment with each other. A fly retaining assembly included in the box comprises a stiff resiliently flexible support plate having opposite major surfaces that extends between the distal edge portions of the cover portions when the cover portions are in the closed position, and has material adapted to be releasably engaged by flies on each of its major surfaces. Releasably engageable means can be provided between the support plate and the hinge for affording pivotal movement of the fly retaining assembly relative to the hinge independent of the cover portions when the cover portions are in their open position. A layer of flexible sealing material can be provided by over molding on each of the major surfaces of the support plate that is in sealing engagement with the edge portion of the adjacent cover portion when the cover portions are in their closed position, and material adapted to be releasably engaged by flies is provided on each major surface of the support plate, in a position that will be surrounded by the side wall parts of the adjacent cover portion when the cover portions are in their closed position. A latch member is provided along a second side of the periphery of the support plate opposite its first side. That latch member has opposite portions each adapted for releasable engagement with a different one of the cover portions to releasably retain the cover portions in their closed position.