Cyproconazole is an agricultural fungicide of the class of azoles, used on cereal crops, coffee, sugar beet, fruit trees and grapes, and peanuts,[2] on sod farms and golf course turf and on wood as a preservative.

[4] Many different formulations exist with imazalil, difenoconazole, prochloraz, propiconazole, chlorothalonil, cyprodinil, fludioxonil, azoxystrobin, and copper.

[3] It is the active ingredient in two foliar fungicides for soybeans in the U.S.: Alto X, and mixed with azoxystrobin in Quadris Xtra, both by Syngenta.

[6]: Appendix II  It can be used on above-ground wood to prevent it from decay from fungi as an alternative to Chromated Copper Arsenate.

The European Community has classified cyproconazole into carcinogen category 3 as limited evidence, into the reproduction risk category 3 as "possible risk of harm to the unborn child", as harmful if swallowed, and dangerous for the environment, because it is very toxic to aquatic organisms, causing long-term adverse effects in the aquatic environment.

[10] Cyproconazole is an endocrine disruptor and has been shown to cause a dose dependent inhibition of progesterone production in human placental cells in vitro.

[11] Cyproconazole as other triazoles inhibits the enzyme cytochrome P-450, so it can no longer demethylate lanosterol, an intermediate needed in ergosterol synthesis.

(package insert Alto 100Syngenta)[citation needed] In the U.S. Sandoz applied in 1988 for registration under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) with the U.S. EPA, and cyproconazole was approved on December 22, 1993.

[18] In Europe, Syngenta had applied for registration in 2009 and the European Food Safety Authority recommended cyproconazole be registered in 2010.