1- Introduction In recent decades, countries around the world have thought about using clean energy carriers as a solution for problems caused by excessive air and environmental pollution. Meanwhile, natural gas consumption has been increased due to less diffusion of carbon dioxide (compared to other fossil fuels) and more environmental sustainability it can cause thus, demand for it has risen to the utmost degree. Iran owns 18% of world total gas reserves which makes it the second-biggest gas owner in the world. Thus, this country can play a prominent role in answering the increased demand for gas in the new atmosphere mentioned above and this can add to its geopolitical prominence. However, in spite of various potential benefits of natural gas for Iran, due to existing challenges, this country has not been able to use its opportunities. In the current research, we study Iran's challenges and opportunities with respect to natural gas, from a geopolitical perspective. 2- Research Method This study has been conducted through using analytical descriptive method. Considering the nature of the studied subject, the needed data has been gathered by using library resources. 3- Discussion With regard to gas reserves, Iran is a very rich country, and by having 29.61 trillion cubic meters of exploitable gas reserves- which consists of 15.8% of proven gas reserves of the world- it has the second-largest gas reserves in the world after Russia. More than half of Iran's gas reserves are located in common gas fields and more than two-thirds of them are placed in non-associated gas fields. Iran's the most important non-associated gas fields are: South Pars, North Pars, Nar, Khangiran. Most of Iran's gas reserves are in southern areas of the country, near Persian Gulf, and many of them are jointly owned by Iran and its neighboring countries. The largest of them is South Pars field that holds half of Iran's gas reserves. Compared to its huge gas reserves and its rank in the world in that respect, Iran's gas production is far less than expected. However, in recent years, an increase in gas production can be witnessed, the amount of which has been 131.2 billion cubic meters in 2009. This amount has been 4.4% of total amount of worldwide gas production and makes Iran the fourth-biggest producer of gas in the world. Concerning gas consumption, in 1993, Iran has consumed 26.6 billion cubic meters of natural gas which has risen to 131.7 billion cubic meters in 2009. These figures show that in 16 years, the amount of gas production in Iran has increased five times. So, we can see that Iran's huge gas reserves pose their own challenges for the country, the most important of which is excessive consumption of natural gas. 4- Conclusion Iran has the second-largest gas reserves in the world. However, this country is facing significant challenges in this respect, the most important of which are excessive consumption of natural gas, common gas fields, amount of burnt gases, and sanctions encouraged by the US and the opposition of that country to the development of Iran's gas sector. These sanctions have caused foreign companies not to invest in Iranian gas market, and thus, Iran's natural gas sector has a lower development rate compared to other gas owners in the world. However, this sector can offer great opportunities for Iran and it can be a base for the development of the country. By exporting gas and changing it into materials with higher added value, Iran's financial development can be accelerated. We should consider that gas is the main fuel used by Iranian petrochemical industries. Furthermore, transferring gas through pipelines to other countries and the resulting long-term contracts can improve Iran's financial and political relationship with other countries. Through this, Iran can reach out to Asian and European regions and by providing gas for them, Iran can increase its national security. This can be achieved through objection of these countries to any kind of sanction or threat imposed against Iran. In other words, Iran's geopolitical and strategic position, combined with its huge gas reserves, can help Iran reach out to international gas markets, which can increase Iran's economic and political power. In addition to that, gas injection to Iran's oil reservoirs can improve recycling and production of oil, the economic benefits of which are more than gas exportation at the moment. Furthermore, by adding to the number of gas-burning vehicles, Iran can reduce the amount of its imported petrol, which is considered as Iran's Achilles' heel in west's view. Iran is facing de facto challenges in natural gas sector which have brought about considerable harms for the country. But its opportunities in this sector are still untapped and for realizing them, Iran should first face the challenges and then solve them. [ABSTRACT FROM AUTHOR]