Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

The easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

Cavanal Hill World Energy Fd Inv Cl (APWEX Quick QuoteAPWEX - Free Report) has a 1.15% expense ratio and 0.6% management fee. APWEX is a Sector - Energy fund, which are comprised of various changing and hugely important industries throughout the massive global energy sector. With yearly returns of 23.47% over the last five years, this fund clearly wins.

Causeway Intl Small Cap Instl (CIISX): 1.1% expense ratio and 1% management fee. CIISX is a Non US - Equity fund. Many of these funds like to allocate across emerging and developed markets, and will often focus on all cap levels. With yearly returns of 15.01% over the last five years, CIISX is an effectively diversified fund with a long reputation of solidly positive performance.

Principal MidCap Institutional (PCBIX): 0.66% expense ratio and 0.57% management fee. PCBIX is a Mid Cap Growth mutual fund. These funds aim to target companies with a market capitalization between $2 billion and $10 billion that are also expected to exhibit more extensive growth opportunities for investors than their peers. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 9.26% over the last five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.