Visible crew/equipment: When the state policemen meet for the first time, the shadow of some equipment is seen on the wall behind them. It falls and you can even hear it. Submitted by Dr Wilson
Continuity: When the girl wakes up in the ambulance, she has much less dirt on her forehead for one shot. It reappears as she lays down. Submitted by Dr Wilson
Continuity: When James Whitmore is attacked by the ant in the Los Angeles sewer system, James Arness arrives, firing an M-1 Garand rifle. In the next scene, he's armed with a Thompson submachine gun.
Continuity: When Patricia is pouring formic acid in the glass, the nurse's hands change position on the girl's chair. Submitted by Dr Wilson
Revealing: When Bob and Ben prepare to gas the ant nest, an ant appears below them. But its legs move too slowly, compared to the speed in which it appears; it rather looks like it is driving across the ground on (hidden) wheels.
Visible crew/equipment: When they find the giant nest in the desert, several parked cars and trucks are visible in the background. It is supposed to be an isolated place. Submitted by Dr Wilson
Factual error: The crew gasses out the ant hill by dropping chemical grenades into the hole. But there are two reality mistakes about the grenades: 1) chemical grenades do not explode; they spray their contents into the area; and 2) considering the size of the ants, the size of their nest must be gigantic, and therefore, it would take more than a hundred grenades to flood it completely with cyanide gas.
Revealing: When the giant ants' nest is taken under fire with bazookas, it can be seen that the back-blast jets are just inserted, e.g. the 'zookas are not actually fired. Also, there is a cut between the 'firing and some of the explosions visible in the same frame.
Revealing: When the radio operator on the 'Viking' is calling for help, an officer can be seen in the background standing calm and rigid in the middle of a pack of giant ants overpowering the rest of the crew...
Visible crew/equipment: When the policemen leaves with the girl, a crewmember's reflection is visible on their car. Submitted by Dr Wilson