A mathematical model predicts seed cotton moisture content during seed cotton conditioning. The model uses air temperature, air mass flow, and seed cotton mass flow to account for the following: heat transfer (sensible heat lost) from the conveying air, heat added to the room, heat added to the seed cotton, heat added to the moisture in the seed cotton to raise the water temperature, and heat added to vaporize the moisture in the seed cotton. Two seed cotton conditioning rates, two mixpoint temperatures, and two levels of moisture content are used to calibrate the model. The model is simplistic in that in considers seed cotton as a whole, and does not split the seed cotton into the lint and seed components. The model has an acceptable R² of 0.80 when regressed against actual seed cotton moisture content. The model does not work well at moisture contents below 6%, but most gin plants have no reason to dry below this level.