This year was particularly difficult, as the donations in May and June dropped to the lowest level in 12 years.
The Penn-Jersey Blood Services Region tells Action News that they are down by 900 units.
Typically, demand for blood goes up in the summer but donations drop. That's because many people are busy travelling and there are fewer students available to donate.
They are in need of all blood types but especially type O-negative. That type of blood can be used for most patients.
The Red Cross said in a statement "We highly encourage all type O negative blood donors who meet the eligibility requirements to double the difference by becoming a double red cell donor. If eligible, you can give to give two donations at once."
To find the location of a blood drive near you or to make an appointment to give, visit the website for the American Red Cross.