Dawkins, 74, branded the news "either a sick joke or sick insult to German generosity" on Thursday after reports emerged that the wealthy Arab state offered to build the mosques in the European country, which is expecting to take 800,000 refugees this year.
While thousands of refugees make the perilous journey across continents to European countries, Saudi Arabia and five other Gulf states have offered zero resettlement places.
Dawkins said the news was "certainly sick", adding he is "horribly afraid it might not be a joke".
The atheist, biologist and author added that the only thing that could be "more useless to refugees in Germany than 200 mosques" was 201 mosques.
German newspaper, The Frankfurter Allgemeine Zeitung, reported the plans to build 200 mosques, quoting Lebanese newspaper al Diyar.
Further details of how Saudi Arabia would build the 200 mosques remain unclear.
Amnesty International reported, "From Asia to Europe, large wealthy countries have turned their backs on Syrian refugees. All six Gulf countries, Russia and Japan have not offered to resettle a single refugee".
Saudi Arabia joins Qatar, United Arab Emirates, Kuwait, Oman and Bahrain in failing to offer any resettlement places.
The Gulf States have received mounting criticism for their "deafening" silence over the refugee crisis.
Last month, Germany's interior minister announced that the country was expecting the arrival of as many as 800,000 refugees this year - four times as many as 2014.
Germany remains the top destination for refugees in Europe, receiving 43% of all asylum applications in the 28-nation European Union.
The news was met with shock and disbelief on social media.